Dissertations / Theses on the topic 'Photonic Integrated Circuits (PICs)'

Mestrado em Engenharia Eletrónica e Telecomunicações
With the continuous evolution of optical communication systems, emerged a need for high-performance optoelectronic elements at lower costs. Photonic packaging plays a key role for the next-generation of optical devices. In this work a standard packaging design rules is described, covering both the electrical and optical-packaging exploring both active and passive adjusting techniques, as well as the thermal management of the photonic integrated circuit (PIC). First a process for fiber-to-chip coupling with custom made ball-lensed fibers, is performed and tested initially in a testing-chip and thereafter in a manufactured practical study-case composed by a silicon holder with an InP distributed feedback (DFB) laser. The process of manufacturing etched V-grooves for fiber alignment is approached in detail. After this, for electrical interconnects and radio frequency (RF) packaging, both wire-bonding and flip-chip technique are discussed, and a characterization of the s-parameters in a PIC with wire-bonding is presented. A technique based on ruthenium-based sensors and platinum and titanium-based sensors for thermal control of the PIC is studied and the tested using a custom made PCB designed exclusively for that purpose.
Com a constante evolução dos sistemas de comunicação óticos veio a necessidade de componentes optoelectrónicos de elevada performance a custos relativamente baixos. O encapsulamento ótico tem um papel chave nos dispositivos óticos de última geração. Neste trabalho são descritas as regras de um processo de encapsulamento padrão, que abrange tanto o encapsulamento elétrico e ótico onde são exploradas técnicas de ajustamento ativas e passivas bem como o controlo térmico do circuito ótico integrado (PIC). No início foi efetuado um processo de acoplamento da fibra ao chip com fibras de lente esférica personalizadas, numa primeira usando um chip de teste e de seguida num caso de estudo prático que consiste numa estrutura composta por um holder de silício com um laser de realimentação distribuída (DFB). É abordado em detalhe o processo de fabricação de V-grooves para o alinhamento da fibra com o chip. De seguida são apresentadas e discutidas as técnicas de wire-bonding e flip-chip para o encapsulamento elétrico e ligação dos conectores de radiofrequência (RF), é feito um estudo onde são apresentados os resultados da caraterização dos parâmetros S de um PIC com wire-bonding. Para o controlo térmico do módulo é apresentada uma técnica baseada em sensores de temperatura de ruténio e sensores de Platina e titânio testada numa PCB personalizada

Mestrado em Engenharia Electrónica e Telecomunicações
Nos dias que correm com a adoção generalizada de smartphones, conteúdos de vídeo, computação em nuvem e redes sociais, o volume de tráfego não para de aumentar. Assim, existe uma procura constante para melhorar a largura de banda das redes existentes. Neste contexto surgiu a Next Generation Passive Optical Network Phase (NG-PON) 2 a qual é um novo standard que vai permitir um aumento da largura de banda que pode chegar aos 80Gbps. O conhecimento dos requisitos do standard NG-PON 2 é importante, para que se possam produzir equipamentos que possam vir a ser utilizados nestas redes. Atualmente existe uma grande evolução nas comunicações óticas. Esta evolução tecnológica levou ao aparecimento de Photonic Integrated Circuits(PICs). Os PICs permitem a integração no mesmo chip de diversos componentes óticos permitindo assim construir circuitos com maior desempenho e fiabilidade. Cada vez mais, existe um grande investimento nesta área, estão inclusivamente a aparecer softwares cujo propósito é permitir aos utilizadores criar e simular PICs, para que estes possam ser posteriormente construídos. É então importante o conhecimento das caraterísticas mais importantes dos blocos que estes softwares permitem simular. Neste trabalho serão testados alguns blocos do “VPItoolkit PDK HHI” que é um toolkit que quando adicionado no software VPItransmissionMaker™, permite simular os componentes produzidos pelo Heinrich Hertz Institute (HHI). Com estes componentes, serão ainda feitas simulações visando a sua utilização em uma rede NG-PON2. Foi também dada grande atenção ao estudo dos Multimode Interference Devices (MMI) dos quais foi feito um modelo em MATLAB. E ao mach Zehnder Modulator (MZM) do qual foi realizada uma animação a demostrar dinamicamente a propagação da Luz dentro dele. Foram ainda sugeridas duas arquiteturas possíveis para um tranceiver a ser utilizado no Optical Network Unit (ONU) em redes NG-PON 2.
Nowadays with the widespread adoption of smartphones, video content, cloud computing and social networks, the volume of traffic is constantly increasing. Therefore, it exists a constant demand to improve the bandwidth of the existing networks. In this context emerged the Next Generation Passive Optical Network Phase (NG-PON 2), which is a new standard that will allow an increase in the bandwidth up to 80 Gbps. The knowledge of the requirements of the standard NG-PON 2 is important, to allow the production of equipment that can be used in these networks. Currently there is a major evolution in optical communications. This technological evolution has led to the emergence of Photonic Integrated Circuits (PICs). By using PICs various optical components can be integrated on the same chip, allowing to build circuits with higher performance and reliability. Currently there is a large investment in this area, software whose purpose is to allow users to create and simulate PICs are starting to appear, to subsequently allow a correct manufacturing of the PICs. It is important to know the most important features of these software blocks and what do they allow to simulate. During this work some blocks from "VPItoolkit PDK HHI" will be tested. "VPItoolkit PDK HHI" is a toolkit that when added in VPItransmissionMaker ™ software allows the simulation of the components produced by the Heinrich Hertz Institute (HHI). With these components, simulations were made to test their use in a NG-PON2 network. It was also given attention to the study of the Multimode Interference Devices (MMI) from which was created a model in MATLAB. And to the Mach Zehnder Modulator (MZM) from which was made an animation to dynamically demonstrate the propagation of light inside him. It was also suggested two possible architectures for a transceiver to be used on the Optical Network Unit (ONU) in NG-PON 2 networks.

Mestrado em Engenharia Electrónica e Telecomunicações
Along with privacy and security, the growth of demand from the consumer for higher bandwidth presents one of the most important modern challenges in telecommunications infrastructures. The researchers were encouraged to nd not only e cient but also the economically viable solutions capable of meeting the growing needs of the consumer. Optical communications are the way that can accompany this growth. The Passive Optical Network (PON) is an architecture that shares the ber bandwidth among several users. There has been a constant study under this topic for the purpose of using all the ber abilities and to nd new solutions to keep the access network simple. Photonic Integrated Circuits (PICs) are a technology that emerged to help the complexity of the hardware that exists nowadays. It is a single chip capable of integrating numerous optical components, which leads to a reduced complexity, size and power consumption. These are the important characteristics that make the PICs a powerful tool to use in several applications. This dissertation presents a monolithic PIC transceiver in the context of Next Generation of Ethernet Passive Optical Network (NG-EPON) which aims to design and implement integrated optical circuits for future access networks. The transceiver architecture is able to be used as an Optical Network Unit (ONU) with a 4 channels approach for 100 Gb/s solutions. The present work contributed for the FUTPON project supported by P2020.
Em par com a privacidade e segurança, a crescente procura do consumidor por maiores larguras de banda apresenta um dos mais importantes desafios modernos das infraestruturas de telecomunicações. Esta procura incentiva assim a investigação de novas soluções não são eficientes, mas também economicamente viáveis, capazes de satisfazer as crescentes necessidades do consumidor. As comunicações óticas apresentam ser o meio apropriado para acompanhar este crescimento. A Rede Óptica Passiva (PON) e uma arquitectura usada para distribuição de fibra ótica ate ao consumidor final. Esta tecnologia permite dividir a largura de banda de uma única fibra por diferentes clientes. Tem havido um estudo constante no âmbito deste tópico para conseguir tirar máximo partido das capacidades da fibra e de modo a encontrar novas soluções para tornar este método mais simples. Os Circuitos Oticos Integrados (PIC) sao uma tecnologia que surge para ajudar na complexidade do hardware existente hoje em dia. Consiste num único chip capaz de integrar vários componentes óticos, o que leva a uma diminuição da complexidade, tamanho e redução do consumo de energia. Estas características fazem com que seja uma tecnologia vantajosa para uso em diferentes aplicações. O desenho e a implementação da arquitectura do transrecetor em formato PIC no contexto da Next Generation of Ethernet Passive Optical Network (NG-EPON), e o principal objectivo desta dissertação onde visa o desenvolvimento circuitos óticos integrados para redes oticas de acesso futuras. Esta arquitectura devera ser utilizada como Optical Network Unit (ONU) contendo 4 canais para atingir 100 Gb/s. Este trabalho contribuiu para o projecto FUTPON suportado pelo P2020.

Mestrado em Engenharia Eletrónica e Telecomunicação
We are living in a time where communications became essential for most of our lives, whether it's in the business world, or in our own homes. The increasing need of higher bandwidth inhibits other networks other than optical ber based ones. Nowadays communications are responsible for a substantial percentage of our energetic footprint, hence Passive Optical Network(PON) are a strong contender for the next step of network implementation. These networks present a low energy consumption because between the transmitter and the receiver the signal stays in the optical domain. Although the increasing needs of bandwidth is almost across the communication world, certain services/identities need more bandwidth whether is download or upload. It's easy to understand that di erent consumers have unique needs. It's necessary to develop an architecture that serves all the costumers, in other words, there is a need for a network that provides high bitrate tra c to the users that needs it but also a network that serves the low end user that is not interested in this increase of bandwidth and therefore price in ation. There is today technologies yet to be widely implemented like NG-PON2 that were not implemented in a large scale because they dont represent a nancial return to the telecom operators simply because there is not enough user that requires the high bandwidth delivered by NG-PON2. It's necessary to nd a solution that includes not only the modern technologies but also the already implemented ones. With the objective of nding a solution for the problems mentioned before, this dissertation has the objective of designing a Photonic Integrated Circuit(PIC) that aims to be a transceiver of a Multitech Network that will be composed by the following technologies: Video-Overlay, XG-PON e NG-PON2. This dissertation presents an approach on Passive Optical Networks( PON) and the standards of the said technologies as well as a study of the components needed to assemble the transceiver using the programs ASPIC and VPI Photonics . In the end, there will be presented an architecture for the transceiver to be used in a Optical Network Unit(ONU), and the respective mask Layout.
Vivemos numa época em que as comunicações se tornaram essenciais para grande parte da nossa vida, seja no mundo empresarial, seja nas nossas habitações. A crescente necessidade de aumento de largura de banda inviabiliza outras redes que não baseadas em braotica. Actualmente as comunicações são responsáveis por uma percentagem substancial dos nossos gastos energéticos, justamente por este facto Passive Optical Networks(PON) sao as principais candidatas ao próximo passo no desenvolvimento de redes. Estas apresentam menor consumo energético, pois entre o emissor e o receptor todo o sinal permanece no domínio óptico. Apesar da necessidade de largura de banda estar a aumentar de um modo transversal no mundo das telecomunicações, certos serviços/entidades necessitam de maiores velocidades tanto em termos de download como em termos de upload. E então fácil de perceber que consumidores diferentes têm necessidades diferentes. E necessário encontrar uma arquitectura que agrade a quem necessita de maiores larguras de banda mas também a quem não necessita de um aumento significativo e que, não está disposto a pagar por este. Existem neste momento tecnologias que ainda não foram implementadas em grandes escalas, como o caso de Next Generation Passive Optical Network (NG-PON2), porque não simbolizam um retorno financeiro para as grande operadores, uma vez que o número de potenciais consumidores de tais velocidades ainda não e substancialmente grande. E necessário encontrar uma solução que não so englobe as novas tecnologias como também as já existentes. Com o objectivo de se encontrar um solução para os problemas acima referidos, este trabalho assenta na elaboração de um Circuito integrado fotonico que visa ser um transrecetor de uma arquitetura multi-tecnologia em que irão ser incorporadas tecnologias como Video-Overlay, 10 Gigabit-capable Passive Optical Network (XG-PON) e NG-PON2. Esta dissertação apresenta uma abordagem as Redes Oticas Passivas e também um estudo feito aos componentes usados no transreceptor usando os programas Aspic e VPI Photonics . Porém ser a apresentado o desenho final do transreceptor que ser a usado numa Optical Network Unit(ONU).

Mestrado em Engenharia Eletrónica e Telecomunicações
In the last years there has been a clear evolution in the world of telecommunications, which goes from new services that need higher speeds and higher bandwidth, until a role of interactions between people and machines, named by Internet of Things (IoT). So, the only technology able to follow this growth is the optical communications. Currently the solution that enables to overcome the day-by-day needs, like collaborative job, audio and video communications and share of les is based on Gigabit-capable Passive Optical Network (G-PON) with the recently successor named Next Generation Passive Optical Network Phase 2 (NG-PON2). This technology is based on the multiplexing domain wavelength and due to its characteristics and performance becomes the more advantageous technology. A major focus of optical communications are Photonic Integrated Circuits (PICs). These can include various components into a single device, which simpli es the design of the optical system, reducing space and power consumption, and improves reliability. These characteristics make this type of devices useful for several applications, that justi es the investments in the development of the technology into a very high level of performance and reliability in terms of the building blocks. With the goal to develop the optical networks of future generations, this work presents the design and implementation of a PIC, which is intended to be a universal transceiver for applications for NG-PON2. The same PIC will be able to be used as an Optical Line Terminal (OLT) or an Optical Network Unit (ONU) and in both cases as transmitter and receiver. Initially a study is made of Passive Optical Network (PON) and its standards. Therefore it is done a theoretical overview that explores the materials used in the development and production of this PIC, which foundries are available, and focusing in SMART Photonics, the components used in the development of this chip. For the conceptualization of the project di erent architectures are designed and part of the laser cavity is simulated using Aspic™. Through the analysis of advantages and disadvantages of each one, it is chosen the best to be used in the implementation. Moreover, the architecture of the transceiver is simulated block by block through the VPItransmissionMaker™ and it is demonstrated its operating principle. Finally it is presented the PIC implementation.
Nos últimos anos tem existido uma evidente evolução no mundo das telecomunicações, que vai desde novos serviços que requerem maiores velocidades e maior largura de banda, a um role de interações entre pessoas e máquinas, designada por Internet of Things (IoT). Assim, a única tecnologia capaz de acompanhar este crescimento são as comunicações óticas. Atualmente a solução que permite colmatar as necessidades do dia-a-dia, tais como trabalhar colaborativamente, comunicar por áudio e vídeo, e partilhar ficheiros, é baseada no Gigabit-capable Passive Optical Network (G-PON) com a mais recente evolução designada por Next Generation Passive Optical Network Phase 2 (NG-PON2). Esta tecnologia baseia-se na multiplexagem no domínio do comprimento de onda e devido às suas características e desempenho torna-se a tecnologia mais vantajosa. Um dos principais focos das comunicações óticas são os Photonic Integrated Circuits (PICs). Estes conseguem englobar num único dispositivo vários componentes, o que simplifica o desenho do sistema ótico, reduzindo o espaço e o consumo de energia e melhora a confiabilidade. Estas caracteristicas tornam este tipo de dispositivos vantajosos para uma série de aplicações, justificando os investimentos no desenvolvimento da tecnologia para um nível muito elevado de desempenho e fiabilidade ao nível dos blocos de construção. Com o objetivo de desenvolver as redes óticas passivas de futuras gerações, este trabalho apresenta o desenho e a implementação de um PIC que visa ser um transrecetor universal para aplicações para NG-PON2. O mesmo PIC pode ser usado como Optical Line Terminal (OLT) ou como Optical Network Unit (ONU) e em ambos os casos como transmissor e recetor. Inicialmente é feito um estudo das redes óticas passivas e os seus standards. Seguidamente é feita uma abordagem teórica que explora um pouco dos materiais usados no desenvolvimento e produção de um PIC, quais as fábricas existentes, focando na SMART Photonics e os componentes usados no desenvolvimento deste chip. Com vista à concetualização do projeto, diferentes arquiteturas são desenhadas e a parte da cavidade do laser é simulada usando o Aspic™. Partindo da análise das vantagens e desvantagens de cada uma delas, é escolhida a melhor para utilizar na implementação. De seguida, a arquitetura do transrecetor é simulada bloco a bloco através do VPItransmissionMaker™ e é demonstrado o seu princípio de funcionamento. Finalmente é apresentada a implementação do PIC.

[EN] The processing of radiofrequency signals using photonics means is a discipline that appeared almost at the same time as the laser and the optical fibre. Photonics offers the capability of managing broadband radiofrequency (RF) signals thanks to its low transmission attenuation, a variety of linear and non-linear phenomena and, recently, the potential to implement integrated photonic subsystems. These features open the door for the implementation of multiple functionalities including optical transportation, up and down frequency conversion, optical RF filtering, signal multiplexing, de-multiplexing, routing and switching, optical sampling, tone generation, delay control, beamforming and photonic generation of digital modulations, and even a combination of several of these functionalities. This thesis is focused on the application of vector processing in the optical domain to radiofrequency signals in two fields of application: optical beamforming, and photonic vector modulation and demodulation of digital quadrature amplitude modulations. The photonic vector control enables to adjust the amplitude and phase of the radiofrequency signals in the optical domain, which is the fundamental processing that is required in different applications such as beamforming networks for direct radiating array (DRA) antennas and multilevel quadrature modulation. The work described in this thesis include different techniques for implementing a photonic version of beamforming networks for direct radiating arrays (DRA) known as optical beamforming networks (OBFN), with the objectives of providing a precise control in terrestrial applications of broadband signals at very high frequencies above 40 GHz in communication antennas, optimizing the size and mass when compared with the electrical counterparts in space application, and presenting new photonic-based OBFN functionalities. Thus, two families of OBFNs are studied: fibre-based true time delay architectures and integrated networks. The first allow the control of broadband signals using dispersive optical fibres with wavelength division multiplexing techniques and advanced functionalities such as direction of arrival estimation in receiving architectures. In the second, passive OBFNs based on monolithically-integrated Optical Butler Matrices are studied, including an ultra-compact solution using optical heterodyne techniques in silicon-on-insulator (SOI) material, and an alternative implementing a homodyne counterpart in germanium doped silica material. In this thesis, the application of photonic vector processing to the generation of quadrature digital modulations has also been investigated. Multilevel modulations are based on encoding digital information in discrete states of phase and amplitude of an electrical signal to enhance spectral efficiency, as for instance, in quadrature modulation. The signal process required for generating and demodulating this kind of signals involves vector processing (phase and amplitude control) and frequency conversion. Unlike the common electronic or digital implementation, in this thesis, different photonic based signal processing techniques are studied to produce digital modulation (photonic vector modulation, PVM) and demodulation (PVdM). These techniques are of particular interest in the case of broadband signals where the data rate required to be managed is in the order of gigabit per second, for applications like wireless backhauling of metro optical networks (known as fibre-to-the-air). The techniques described use optical dispersion in optical fibres, wavelength division multiplexing and photonic up/down conversion. Additionally, an optical heterodyne solution implemented monolithically in a photonic integrated circuit (PIC) is also described.
[ES] El procesamiento de señales de radiofrecuencia (RF) utilizando medios fotónicos es una disciplina que apareció casi al mismo tiempo que el láser y la fibra óptica. La fotónica ofrece la capacidad de manipular señales de radiofrecuencia de banda ancha, una baja atenuación, procesados basados en una amplia variedad de fenómenos lineales y no lineales y, recientemente, el potencial para implementar subsistemas fotónicos integrados. Estas características ofrecen un gran potencial para la implementación de múltiples funcionalidades incluyendo transporte óptico, conversión de frecuencia, filtrado óptico de RF, multiplexación y demultiplexación de señales, encaminamiento y conmutación, muestreo óptico, generación de tonos, líneas de retardo, conformación de haz en agrupaciones de antenas o generación fotónica de modulaciones digitales, e incluso una combinación de varias de estas funcionalidades. Esta tesis se centra en la aplicación del procesamiento vectorial en el dominio óptico de señales de radiofrecuencia en dos campos de aplicación: la conformación óptica de haces y la modulación y demodulación vectorial fotónica de señales digitales en cuadratura. El control fotónico vectorial permite manipular la amplitud y fase de las señales de radiofrecuencia en el dominio óptico, que es el procesamiento fundamental que se requiere en diferentes aplicaciones tales como las redes de conformación de haces para agrupaciones de antenas y en la modulación en cuadratura. El trabajo descrito en esta tesis incluye diferentes técnicas para implementar una versión fotónica de las redes de conformación de haces de en agrupaciones de antenas, conocidas como redes ópticas de conformación de haces (OBFN). Se estudian dos familias de redes: arquitecturas de retardo en fibra óptica y arquitecturas integradas. Las primeras permiten el control de señales de banda ancha utilizando fibras ópticas dispersivas con técnicas de multiplexado por división de longitud de onda y funcionalidades avanzadas tales como la estimación del ángulo de llegada de la señal en la antena receptora. En la segunda, se estudian redes de conformación pasivas basadas en Matrices de Butler ópticas integradas, incluyendo una solución ultra-compacta utilizando técnicas ópticas heterodinas en silicio sobre aislante (SOI), y una alternativa homodina en sílice dopado con germanio. En esta tesis, también se han investigado técnicas de procesado vectorial fotónico para la generación de modulaciones digitales en cuadratura. Las modulaciones multinivel codifican la información digital en estados discretos de fase y amplitud de una señal eléctrica para aumentar su eficiencia espectral, como por ejemplo la modulación en cuadratura. El procesado necesario para generar y demodular este tipo de señales implica el procesamiento vectorial (control de amplitud y fase) y la conversión de frecuencia. A diferencia de la implementación electrónica o digital convencional, en esta tesis se estudian diferentes técnicas de procesado fotónico tanto para la generación de modulaciones digitales (modulación vectorial fotónica, PVM) como para su demodulación (PVdM). Esto es de particular interés en el caso de señales de banda ancha, donde la velocidad de datos requerida es del orden de gigabits por segundo, para aplicaciones como backhaul inalámbrico de redes ópticas metropolitanas (conocida como fibra hasta el aire). Las técnicas descritas se basan en explotar la dispersión cromática de la fibra óptica, la multiplexación por división de longitud de onda y la conversión en frecuencia. Además, se presenta una solución heterodina implementada monolíticamente en un circuito integrado fotónico (PIC).
[CAT] El processament de senyals de radiofreqüència (RF) utilitzant mitjans fotònics és una disciplina que va aparèixer gairebé al mateix temps que el làser i la fibra òptica. La fotònica ofereix la capacitat de manipular senyals de radiofreqüència de banda ampla, una baixa atenuació, processats basats en una àmplia varietat de fenòmens lineals i no lineals i, recentment, el potencial per implementar subsistemes fotònics integrats. Aquestes característiques ofereixen un gran potencial per a la implementació de múltiples funcionalitats incloent transport òptic, conversió de freqüència, filtrat òptic de RF, multiplexació i demultiplexació de senyals, encaminament i commutació, mostreig òptic, generació de tons, línies de retard, conformació de feix en agrupacions d'antenes i la generació fotònica de modulacions digitals, i fins i tot una combinació de diverses d'aquestes funcionalitats. Aquesta tesi es centra en l'aplicació del processament vectorial en el domini òptic de senyals de radiofreqüència en dos camps d'aplicació: la conformació òptica de feixos i la modulació i demodulació vectorial fotònica de senyals digitals en quadratura. El control fotònic vectorial permet manipular l'amplitud i la fase dels senyals de radiofreqüència en el domini òptic, que és el processament fonamental que es requereix en diferents aplicacions com ara les xarxes de conformació de feixos per agrupacions d'antenes i en modulació multinivell. El treball descrit en aquesta tesi inclou diferents tècniques per implementar una versió fotònica de les xarxes de conformació de feixos en agrupacions d'antenes, conegudes com a xarxes òptiques de conformació de feixos (OBFN), amb els objectius de proporcionar un control precís en aplicacions terrestres de senyals de banda ampla a freqüències molt altes per sobre de 40 GHz en antenes de comunicacions, optimitzant la mida i el pes quan es compara amb els homòlegs elèctrics en aplicacions espacials, i la presentació de noves funcionalitats fotòniques per agrupacions d'antenes. Per tant, s'estudien dues famílies de OBFNs: arquitectures de retard en fibra òptica i arquitectures integrades. Les primeres permeten el control de senyals de banda ampla utilitzant fibres òptiques dispersives amb tècniques de multiplexació per divisió en longitud d'ona i funcionalitats avançades com ara l'estimació de l'angle d'arribada del senyal a l'antena receptora. A la segona, s'estudien xarxes de conformació passives basades en Matrius de Butler òptiques en fotònica integrada, incloent una solució ultra-compacta utilitzant tècniques òptiques heterodinas en silici sobre aïllant (SOI), i una alternativa homodina en sílice dopat amb germani. D'altra banda, també s'ha investigat en aquesta tesi tècniques de processament vectorial fotònic per a la generació de modulacions digitals en quadratura. Les modulacions multinivell codifiquen la informació digital en estats discrets de fase i amplitud d'un senyal elèctric per augmentar la seva eficiència espectral, com ara la modulació en quadratura. El processat necessari per generar i desmodular aquest tipus de senyals implica el processament vectorial (control d'amplitud i fase) i la conversió de freqüència. A diferència de la implementació electrònica o digital convencional, en aquesta tesi s'estudien diferents tècniques de processament fotònic tant per a la generació de modulacions digitals (modulació vectorial fotònica, PVM) com per la seva demodulació (PVdM). Això és de particular interès en el cas de senyals de banda ampla, on la velocitat de dades requerida és de l'ordre de gigabits per segon, per a aplicacions com backhaul sense fils de xarxes òptiques metropolitanes (coneguda com fibra fins l'aire). Les tècniques descrites es basen en explotar la dispersió cromàtica de la fibra òptica, la multiplexació per divisió en longitud d'ona i la conversió en freqüència. A més, es prese
Piqueras Ruipérez, MÁ. (2016). Photonic Vector Processing Techniques for Radiofrequency Signals [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/63264
TESIS

Optical polymers are a subject of research and industry implementation for many decades. Optical polymers are inexpensive, easy to process and flexible enough to meet a broad range of application-specific requirements. These advantages allow a development of cost-efficient polymer photonic integrated circuits for on-chip optical communications. However, low refractive index contrast between core and cladding limits light confinement in a core and, consequently, integrated polymer device miniaturization. Also, polymers lack active functionality like light emission, amplification, modulation, etc. In this work, we improved a performance of integrated polymer waveguides and demonstrated active waveguide devices. Also, we present novel Si QD/polymer optical materials. In the integrated device part, we demonstrate optical waveguides with enhanced performance. Decreased radiation losses in air-suspended curved waveguides allow low-loss bending with radii of only 15 µm, which is far better than >100 µm for typical polymer waveguides. Another study shows a positive effect of thermal treatment on acrylate waveguides. By heating higher than polymer glass transition temperature, surface roughness is reflown, minimizing scattering losses. This treatment method enhances microring resonator Q factor more than 2 times. We also fabricated and evaluated all-optical intensity modulator based on PMMA waveguides doped with Si QDs. We developed novel hybrid optical materials. Si QDs are encapsulated into PMMA and OSTE polymers. Obtained materials show stable photoluminescence with high quantum yield. We achieved the highest up to date ~65% QY for solid-state Si QD composites. Demonstrated materials are a step towards Si light sources and active devices. Integrated devices and materials presented in this work enhance the performance and expand functionality of polymer PICs. The components described here can also serve as building blocks for on-chip sensing applications, microfluidics, etc.

QC 20171207

Integrated optics as a platform for signal processing offers significant benefits such as large bandwidth, low loss, and a potentially high degree of reconfigurability. Silicon (Si) has unique advantages as a material platform for integration, as well as properties such as a strong thermo-optic mechanism that allows for the realization of highly reconfigurable photonic systems. Chapter 1 is devoted to the discussion of these advantages, and Chapter 2 provides the theoretical background for the analysis of integrated Si-photonic devices. The thermo-optic property of Si, while proving extremely useful in facilitating reconfiguration, can turn into a nuisance when there is a need for thermally stable devices on the photonic chip. Chapter 3 presents a technique for resolving this issue without relying on a dynamic temperature stabilization process. Temperature-insensitive (or “athermal”) Si microdisk resonators with low optical loss are realized by using a polymer overlayer whose thermo-optic property is opposite to that of Si, and TiO2 is introduced as an alternative to polymer to deal with potential CMOS-compatibility issues. Chapter 4 demonstrates an ultra-compact, low-loss, fully reconfigurable, and high-finesse integrated photonic filter implemented on a Si chip, which can be used for RF-photonic as well as purely optical signal processing purposes. A novel, thermally reconfigurable reflection suppressor is presented in Chapter 5 for on-chip feedback elimination which can be critical for mitigating spurious interferences and protecting lasers from disturbance. Chapter 6 demonstrates a novel device for on-chip control of optical fiber polarization. Chapter 7 deals with select issues in the implementation of Si integrated photonic circuits. Chapter 8 concludes the dissertation.

Photonic signal processing has been considered a promising solution to overcome the inherent bandwidth limitations of its electronic counterparts. Over the last few years, an impressive range of photonic integrated signal processors have been proposed with the technological advances of III-V and silicon photonics, but the signal processors offer limited tunability or reconfigurability, a feature highly needed for the implementation of programmable photonic signal processors. In this thesis, tunable and reconfigurable photonic signal processors are studied. Specifically, a photonic signal processor based on the III-V material system having a single ring resonator structure for temporal integration and Hilbert transformation with a tunable fractional order and tunable operation wavelength is proposed and experimentally demonstrated. The temporal integrator has an integration time of 6331 ps, which is an order of magnitude longer than that provided by the previously reported photonic integrators. The processor can also provide a continuously tunable fractional order and a tunable operation wavelength. To enable general-purpose signal processing, a reconfigurable photonic signal processor based on the III-V material system having a three-coupled ring resonator structure is proposed and experimentally demonstrated. The reconfigurability of the processor is achieved by forward or reverse biasing the semiconductor optical amplifiers (SOAs) in the ring resonators, to change the optical geometry of the processor which allows the processor to perform different photonic signal processing functions including temporal integration, temporal differentiation, and Hilbert transformation. The integration time of the signal processor is measured to be 10.9 ns, which is largely improved compared with the single ring resonator structure due to a higher Q-factor. In addition, 1st, 2nd, and 3rd of temporal integration operations are demonstrated, as well as a continuously tunable order for differentiation and Hilbert transformation. The tuning range of the operation wavelength is 0.22 nm for the processor to perform the three functions. Compared with the III-V material system, the CMOS compatible SOI material system is more cost effective, and it offers a smaller footprint due to the strong refractive index contrast between silicon and silica. Active components such as phase modulators (PMs) can also be implemented. In this thesis, two photonic temporal differentiators having an interferometer structure to achieve active and passive fractional order tuning are proposed and experimentally demonstrated. For both the active and passive temporal differentiators, the fractional order can be tuned from 0 to 1. For the active temporal differentiator, the tuning range of the operation wavelength is 0.74 nm. The use of the actively tunable temporal differentiator to perform high speed coding with a data rate of 16 Gbps is also experimentally demonstrated.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references.
The optical logic unit cell is the photonic analog to transistor-transistor logic in electronic devices. Active devices such as InP-based semiconductor optical amplifiers (SOA) emitting at 1550 nm are vertically integrated with passive waveguides using the asymmetric twin waveguide technique and the SOAs are placed in a Mach-Zehnder interferometer (MZI) configuration. By sending in high-intensity pulses, the gain characteristics, phase-shifting, and refractive indices of the SOA can be altered, creating constructive or deconstructive interference at the MZI output. Boolean logic and wavelength conversion can be achieved using this technique, building blocks for optical switching and signal regeneration. The fabrication of these devices is complex and the fabrication of two generations of devices is described in this thesis, including optimization of the mask design, photolithography, etching, and backside processing techniques. Testing and characterization of the active and passive components is also reported, confirming gain and emission at 1550 nm for the SOAs, as well as verifying evanescent coupling between the active and passive waveguides. In addition to the vertical integration of photonic waveguides, Esaki tunnel junctions are investigated for vertical electronic integration. Quantum dot formation and growth via molecular beam epitaxy is investigated for emission at the technologically important wavelength of 1310 nm. The effect of indium incorporation on tunnel junctions is investigated. The tunnel junctions are used to epitaxially link multiple quantum dot active regions in series and lasers are designed, fabricated, and tested.
by Ryan Daniel Williams.
Ph.D.

In this thesis, several aspects of GaAsSb/AlSb multiple quantum well (MQW) heterostructures have been studied. First, it was shown that the GaAsSb MQWs with a direct band gap near 1.5 μm at room temperature could be monolithically integrated with AlGaSb/AlSb or AlGaAsSb/AlAsSb Bragg mirrors, which can be applied to Vertical Cavity Surface Emitting Lasers (VCSELs). Secondly, an enhanced photoluminescence from GaAsSb MQWs was reported. The photoluminescence strength increased dramatically with arsenic fraction as conjectured. The peak photoluminescence from GaAs(0.31)Sb(0.69) was 208 times larger than that from GaSb. Thirdly, the strong photoluminescence from GaAsSb MQWs and the direct nature of the band gap near 1.5 μm at room temperature make the material favorable for intermixing studies. The samples were treated with ion implantation followed by rapid thermal annealing (RTA). A band gap blueshift as large as 198 nm was achieved with a modest ion dose and moderate annealing temperature. Photoluminescence strength for implanted samples generally increased with the annealing temperature. The energy blueshift was attributed to the interdiffusion of both the group III and group V sublattices. Finally, based on the interesting properties of GaAsSb MQWs, including the direct band gap near 1.5 μm, strong photoluminescence, a wide range of wavelength (1300 – 1500 nm) due to ion implantation-induced quantum well intermixing (QWI), and subpicosecond spin relaxation reported by Hall et al, we proposed to explore the possibilities for ultra-fast optical switching by investigating spin dynamics in semiconductor optical amplifiers (SOAs) containing InGaAs and GaSb MQWs. For circularly polarized pump and probe waves, the numerical simulation on the modal indices showed that the difference between the effective refractive index of the TE and TM modes was quite large, on the order of 0.03, resulting in a significant phase mismatch in a traveling length larger than 28 μm. Thus the FWM conversion efficiency was exceedingly small and the FWM mechanism in SOAs used for investigation of all-optical polarization switching was strongly limited.

This doctoral dissertation deals with the design, fabrication and characterization of state-of-the-art Photonic Integrated Circuits (PICs) for non-linear applications. Silicon PICs is a technology mainly used for application in telecommunications and quantum optics. The strong third order non-linearity of silicon makes it also attractive for non-linear PIC design. In FWM applications, SOI technology can be used not only for non-linear generation but also to fabricate photonic filters to remove the residual pump. This thesis deals with three requirements for the realisation of on-chip FWM optical devices, the dual polarisation rejection of the pump on-chip and the integration and stabilisation of the FWM source and optical filter. In this work two of the most used SOI photonic integrated filters, ring resonators and Bragg gratings, are presented. These devices present two different solutions for high extinction(≈ 60 dB) dual polarisation filtering. An integrated structure of non-linear source and filter is presented. The device used for non-linear generation is then monolithically integrated with a novel ring resonators cascade filter technology. FWM experiments were carried out obtaining an on chip pump high dual polarisation extinction of 62 dB with a low insertion loss for the propagating signal and idler of only 1.8 dB.The realisation of a microprocessor feedback loop stabilisation system integrated with SOI non-linear structures is also demonstrated. The system is based on a local thermal heater element on-chip used to stabilise the PICs against thermal refractive index variations. Using this method, a silicon π-phase shifted grating with a cavity Q-factor of 40k is demonstrated to operate over an ambient temperature detuning range of 40 oC and injection wavelength range of 1.5 nm, nearly 3 orders of magnitude greater than the resonant cavity line width. The last part of this work is dedicated to the description of a custom made laser photolitography system for rapid prototyping of PIC designs, a tool designed to overcome the costs of the typical lithography systems and drastically decrease the time required for multiple micro-fabrications. The hardware and the software created for this tool are presented together with the first results on the fabrication of SU-8 Photoresist (SU − 8) on Silicon Dioxide (SiO2) waveguides, bends, Mach Zehnder interferometers and ring resonators.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2004.
Includes bibliographical references (leaves 149-158).
This thesis describes the development of advanced laser resonators and applications of laser-induced micromachining for photonic circuit fabrication. Two major advantages of laser-induced micromachining are direct patterning and writing on large areas of substrates at high speed following the exposure of laser light, without using complicated photomask steps. For passive photonic devices fabrication, a novel femtosecond laser with unprecedented low repetition rates of 4 MHz is demonstrated to generate high intensity pulses, as high as 1.25 MW with 100 nJ pulse energies and 80 fs pulse durations directly from this laser resonator, without using any active devices or amplifiers. These high intensity pulses are applied to transparent glass materials to demonstrate micromachining of waveguides, gratings, couplers, and three dimensional waveguides and their beam couplings. Active and passive semiconductor devices can be monolithically integrated by employing high energy laser pulses to locally disorder quantum well regions. The 45 nm bandgap shifts at 1.55 ptm with a standard Q-switched Nd:YAG laser at 535 nm are realized. Finally, unidirectional semiconductor ring lasers for high-density integration are developed as a potential application to photonic integrated circuits. Hybrid semiconductor S-crossover and retro-reflected ring lasers, as prototypes for unidirectional operation, are built and result in up to 21.5 dB and 24.5 dB of counter-mode suppression ratio, respectively, which is in good agreement with theoretical predictions.
by Seong-Ho Cho.
Ph.D.

Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 63-65).
Optical communication systems have many advantages over communication systems that operate in the radio-frequency range, including decreased size, weight, and power consumption and increased bandwidth. As a result, optical communication systems are emerging as the ideal choice in many resource-constrained links such as those deployed on spacecraft. This thesis presents progress on development of a programmable nanophotonic processor (PNP) for implementing a high-fidelity reconfigurable optical transceiver at the telecommunications wavelength. By encoding information in multiple spatial modes and detecting jointly over the modes using a unitary transform prior to detection, one can in principle attain Holevo-limited channel capacity in the low mean photon number regime. Since the PNP offers dynamic reprogrammability, one can also, in principle, correct for wavefront distortion in the channel. We present a setup, calibration protocols, and preliminary results towards a turbulence-resistant integrated BPSK transmitter and joint detection receiver channel that achieves superadditive channel capacity in the low mean photon number regime.
by Mihika Prabhu.
S.M.

Ce travail de thèse présente une étude sur les propriétés de nanostructures de type bâtonnets quantiques et de leur application pour les télécommunications optiques. Durant la dernière décennie, ces nanostructures, ont démontré des propriétés optiques et électroniques intéressantes en raison notamment d’un fort confinement quantique dans les trois dimensions d'espace. Cette thèse porte sur la conception et la fabrication d'émetteurs optiques intégrés à base de ce matériau et de leur implémentation dans des systèmes de communication. La première partie de ce travail analyse les propriétés de ces nanostructures, théorique et expérimentale. Elles sont utilisées comme matériau actif de lasers modulés directement en amplitude. Les propriétés dynamiques de ces lasers sont ensuite évaluées et des transmissions sur fibre optique entre 0 et 100 km sont ensuite démontrées en utilisant un filtre étalon permettant d’augmenter en particulier le taux d’extinction dynamique. En s’appuyant sur cette démonstration basée sur des éléments discrets, une version monolithique intégrant un laser et un résonateur en anneaux a été réalisée. La dernière partie de ce travail porte sur des lasers à blocage de mode à base de ce matériau et en particulier sur les méthodes d’intégration sur substrat InP. En particulier, un design de miroir de Bragg innovant a été développé à cet effet et une démonstration d'un laser a blocage de mode intégré avec un amplificateur optique à semi-conducteur a finalement été réalisée
This PhD dissertation presents a study on the properties of the novel quantum dash nanostructures and their properties for application in optical telecommunications. Over the last decade, scientific community has gained considerable interest over these nanostructures and several demonstrations have been made on their interesting optical and electronic properties, notably owing to their strong quantum confinement. This dissertation focuses on conception, fabrication and system demonstration of integrated optical transmitters based on quantum dash material. A first part of this work analyses the properties of qdashes theoretically and experimentally for their use as an active material in directly modulated lasers. The dynamic properties of this material are then evaluated leading to an optical transmission distances in range of 0-100km under direct modulation. The transmission is particularly studied with a passive optical filter to enhance the dynamic extinction ratio, the use of such passive filters is studied in detail. An innovative and fully integrated optical transmitter is finally demonstrated by integrating a ring-resonator filter to a distributed feedback laser. The second part of this work focuses on mode locked lasers based on this material and in particular the methods of integration of such devices on InP are explored. Thus an innovative Bragg mirror design is developed leading to a mode locked laser integrated with a semiconductor optical amplifier

La spectroscopie dans le moyen-infrarouge est une méthode universelle pour identifier les substances chimiques et biologiques, car la plupart des molécules ont leurs résonances de vibration et de rotation dans cette plage de longueurs d'onde. Les systèmes moyen infrarouge disponibles dans le commerce reposent sur des équipements volumineux et coûteux, tandis que de nombreux efforts sont maintenant consacrés à la réduction de leur taille et leur intégration sur circuits intégrés. L’utilisation de la technologie silicium pour la réalisation de circuits photoniques dans le moyen-infrarouge présente de nombreux avantages: fabrication fiable, à grand volume, et réalisation de circuits photoniques à hautes performances, compacts, légers et à faible consommation énergétique. Ces avantages sont particulièrement intéressant pour les systèmes de détection spectroscopique moyen infrarouge, qui besoin d'être portable et à faible coût. Parmi les différents matériaux disponibles en photonique silicium, les alliages silicium-germanium (SiGe) à forte concentration en Ge sont particulièrement intéressants en raison de la grande fenêtre de transparence du Ge, pouvant atteindre 15 µm. Dans ce contexte, l'objectif de cette thèse est d'étudier une nouvelle plate-forme SiGe à forte concentration en Ge, pour la démonstration de circuits photoniques moyen infra rouge. Cette nouvelle plate-forme devrait bénéficier d'une large gamme de transparence en longueurs d'onde de transparence et de la possibilité d’ajuster les propriétés des guides optiques (indice effectif, dispersion,…). Au cours de cette thèse, différentes plates-formes basées sur différents profils graduels du guide d’onde ont été étudiées. Tout d'abord, il a été démontré qu’il était possible d’obtenir des guides présentant de faibles pertes optiques inférieures à 3 dB/cm dans une large plage de longueurs d'onde, de 5,5 à 8,5 µm. Une preuve de concept de détection de molécules, basée sur l'absorption de la partie évanescent du mode optique a ensuite été démontrée. Ensuite, les composants formant les briques de base classiques de la photonique intégrée ont été étudiés. Les premières cavités intégrées ont été réalisées à 8 µm. Deux configurations ont été étudiées : des cavité Fabry-Perot utilisant des miroirs de Bragg intégrés dans les guides d’onde et des résonateurs en anneau. Un spectromètre à transformée de Fourier fonctionnant sur une large bande spectrale, et pour les deux polarisations de la lumière a également été démontré. Tous ces résultats reposent sur la conception des matériaux et des composants, la fabrication en salle blanche et la caractérisation expérimentale. Ce travail a été effectué dans le cadre du projet européen INsPIRE en collaboration avec le Pr. Giovanni Isella de Politecnico Di Milano
Mid-infrared (mid-IR) spectroscopy is a nearly universal way to identify chemical and biological substances, as most of the molecules have their vibrational and rotational resonances in the mid-IR wavelength range. Commercially available mid-IR systems are based on bulky and expensive equipment, while lots of efforts are now devoted to the reduction of their size down to chip-scale dimensions. The use of silicon photonics for the demonstration of mid-IR photonic circuits will benefit from reliable and high-volume fabrication to offer high performance, low cost, compact, lightweight and power consumption photonic circuits, which is particularly interesting for mid-IR spectroscopic sensing systems that need to be portable and low cost. Among the different materials available in silicon photonics, Germanium (Ge) and Silicon-Germanium (SiGe) alloys with a high Ge concentration are particularly interesting because of the wide transparency window of Ge up to 15 µm. In this context, the objective of this thesis is to investigate a new Ge-rich graded SiGe platform for mid-IR photonic circuits. Such new plateform was expected to benefit from a wide transparency wavelength range and a high versatility in terms of optical engineering (effective index, dispersion, …). During this thesis, different waveguides platforms based on different graded profiles have been investigated. First it has been shown that waveguides with low optical losses of less than 3 dB/cm can be obtained in a wide wavelength range, from 5.5 to 8.5 µm. A proof of concept of sensing based on the absorption of the evanescent component of the optical mode has then been demonstrated. Finally, elementary building blocs have been investigated. The first Bragg mirror-based Fabry Perot cavities and racetrack resonators have been demonstrated around 8 µm wavelength. A broadband dual-polarization MIR integrated spatial heterodyne Fourier-Transform spectrometer has also been obtained. All these results rely on material and device design, clean-room fabrication and experimental characterization. This work was done in the Framework of EU project INsPIRE in collaboration with Pr. Giovanni Isella from Politecnico Di Milano

The ability to integrate multiple photonic devices on a single substrate has turned out to be very advantageous in the fabrication of components for optical communication networks. For example, improved fiber coupling can be achieved by integrating a modulator with an optical mode converter. However, current technology is very limited in its ability to fabricate such photonic integrated circuits (PIC).
We report on a selective area epitaxy (SAE) process suitable for the fabrication of a PIC. The process includes a quantitative model, which for the first time, is capable of predicting the growth rate and composition of thin films selectively deposited by metalorganic chemical vapour deposition in areas close to the dielectric mask as well as areas several microns away. The accuracy of the model is demonstrated by comparing simulation results with experimental measurements of the thickness and composition profiles obtained by surface profilometry and energy dispersed X-ray respectively.
The process is applied to the fabrication of an elecroabsorption modulator and optical mode converter, monolithically integrated on an InP substrate. As part of the fabrication, quantitative modeling of the converter waveguide core deposition is employed to achieve a thickness profile previously designed by beam propagation calculations. Modeling is also used to predict the composition and strain shifts introduced by selective deposition, enabling the composition to be designed such that the maximum strain is minimized. Device measurements demonstrate that SAE is successfully used for the fabrication of a PIC with characteristics superior to those found in conventional devices.

Mutually coupled lasers have received much attention in recent years as a source of rich non linear dynamics, enabling optical configurations for new ranges of applications, particularly chaos-based encrypted communications. However the overall dynamics of the mutually coupled configuration has not received so much attention, particularly with regard to the practical range of parameters for the lasers. This thesis investigates the dynamics of the mutually coupled lasers system in respect of all the significant causes and influences on dynamics. Furthermore, the lasers here are widely tuneable, representing the more complex tunable devices found in modern communications systems. The system investigated is both self and mutually-coupled, which represents the mechanism which may arise in modern photonic integrated circuits (PICs), and therefore has relevance to the design and operation of such devices. However the configuration here has parallels with, and great relevance to the non self-coupled configuration, and the conditions for this (such as phase) are highlighted. The dynamics are investigated experimentally in an integrated device using some of the latest technology to obtain time series of a high bandwidth, in addition to optical spectra and high resolution radio-frequency spectra. These enable a range of dynamic analysis tools such as the correlation dimension (for which a unique algorithm is described) to be applied, and this provides insight into the dynamics of the system. The PIC is also modelled using a thorough and realistic travelling wave method, which is required for the complex system of multiple coupling sources, with varying delays and optical paths which may be found in modem PICs. The PIC parameters such as coupling magnitude are first investigated experimentally and then various methods are used to calibrate these relations within the travelling wave program. A number of tuning properties of the OBR laser(s) within the PIC are then given in both the model and experiment, with good correlation between the two found. The principal investigations of dynamics in the PIC are then described. This commences with details of the overall dynamics of the PIC, and the dynamic analysis tools required to represent and quantify these dynamics. The effects of varying coupling between the lasers over a range of frequency detuning values are then studied. The effects of coupling magnitude are quantified with respect to an overall transition to chaos in the system, and overall dynamic trends. Correlation is found between the experimental and modelled results. The system of phases in the PIC are then investigated, and this has impact on the permutations of phase between oscillators in respect of conditions such as spatial symmetry and index dispersion. The control of the system of phases as a single ensemble is then described, and this is found to produce a rich variety of dynamic behaviour from this subtle parameter. Phase controlled dynamics are demonstrated experimentally, and correlated dynamics in the model are demonstrated. Finally four wave mixing, which is present in many optical configurations is shown to have a profound effect on dynamics in the model, and experimental results are presented supporting these results. These parameters of coupling magnitude, detuning, phase and four wave mixing level represent the major contributing causes of dynamics in multi-laser PICs. The results presented here have implications for the design and use of PICs, either to exploit or avoid these dynamics.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 149-154).
Electronic-photonic integrated circuits have the potential to circumvent many of the performance bottlenecks of electronics. To achieve the full benefits of integrating photonics with electronics it is generally believed that wavelength-division multiplexing is needed; requiring an integrated optical device capable of multiplexing/demultiplexing operations. One such device is a bank of microring-resonator filters with precisely spaced resonant frequencies. In this work, a fabrication strategy based on scanning-electron-beam lithography (SEBL) is presented for precisely controlling the resonant frequency of microring-resonator filters. Using this strategy it is possible to achieve dimensional control, on the tens-of- picometer scale, as required for microring-resonator filter banks. To correct for resonant-frequency errors present after fabrication, two forms of postfabrication tuning, one dynamic and one static, are demonstrated. It is also shown that hydrogen silsesquioxane (HSQ) can be converted into a high-quality overcladding for photonic devices by optimizing the annealing process. Finally, a postfabrication technique of localized substrate removal is presented, enabling the integration of photonics with CMOS electronics. Second-order microring-resonator filter banks were fabricated using SiNx and Si as the high -index core materials. By controlling the electron-beam-exposure dose it is possible to change the average microring-waveguide width to a precision better than 75 pm, despite the 6 nm SEBL address grid. Using postfabrication tuning the remaining resonant-frequency errors can be reduced to less than 1 GHz.
(cont.) By annealing HSQ in a an 02 atmosphere using rapid thermal processing, it is possible to create thick overcladding layers that have essentially the same optical properties as SiO2 with the excellent gap-filling and planarization properties of HSQ. Using XeF2 to locally etch an underlying Si substrate, waveguides with a propagation loss of -10 dB/cm were fabricated out of polysilicon deposited on 50 nm of SiO2.
by Charles W. Holzwarth, Ill.
Ph.D.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Physics, 2000.
Includes bibliographical references (p. 139-143).
In this thesis we investigate novel photonic crystal devices that can be used as building blocks of all-optical circuits. We contrast the behavior of light in photonic crystal systems and in their traditional counterparts. We exhibit that bends in photonic crystals are able to transmit light with over 90% efficiency for large bandwidths and with 100% efficiency for specific frequencies. In contrast to traditional waveguides, bound states in photonic crystal waveguides can also exist in constrictions and above the cutoff frequency. We discuss how to lower reflections encountered when photonic crystal waveguides are terminated, both in an experimental setup as well as in numerical simulations. We show that light can be very efficiently coupled into and out of photonic crystal waveguides using tapered dielectric waveguides. In time-domain simulations of photonic crystal waveguides, spurious reflections from cell edges can be eliminated by terminating the waveguide with a Bragg reflector waveguide. We demonstrate novel lasing action in two-dimensional photonic crystal slabs with gain media, where lasing occurs at saddle points in the band structure, in contrast to one-dimensional photonic crystals. We also design a photonic crystal slab with organic gain media that has a TE-like pseudogap. We demonstrate that such a slab can support a high-Q defect mode, enabling low threshold lasing, and we discuss how the quality factor depends on the design parameters. We also propose to use two dimensional photonic crystal slabs as directionally efficient free-space couplers. We draft methods to calculate the coupling constant both numerically and analytically, using a finite-difference time-domain method and the volume current method with a Green's function approach, respectively.
by Attila Mekis.
Ph.D.

The American Institute for Manufacturing Integrated Photonics (AIM Photonics) is focused on developing an end- to- end integrated photonics ecosystem in the U.S., including domestic foundry access, integrated design tools, automated packaging, assembly and test, and workforce development. This paper describes how the institute has been structured to achieve these goals, with an emphasis on advancing the integrated photonics ecosystem. Additionally, it briefly highlights several of the technological development targets that have been identified to provide enabling advances in the manufacture and application of integrated photonics.

In recent years much effort has been carried out to make integrated photonics a widespread technology to be exploited in current optical communication industry. It is hoped by substituting microelectronics by photonic chips and keeping the light carried by optical fibers in light domain for further processing, the cost and speed of communications will be vastly improved. Although this transition is challenging in various aspects, here in this thesis some of these issues are discussed and addressed. In this thesis firstly the limitations of current simulation tools for analysis of wide range of photonic devices is pointed out. Structures based on photonic crystals are taken into consideration at this point which because of finely detailed structures have shown to be challenging to be analyzed by conventional tools. In this regard three different common structures based on photonic crystals in both resonant and non-resonant regimes have been considered: lamellar gratings, metamaterials for Lüneburg lens and Bragg gratings in a LC-DFB laser. For each structure, an analytical method or homogenization approach is proposed which is claimed to be faster for analysis of such components than numerical methods. Comparisons of the results with conventional numerical methods prove accuracies of each approach. Furthermore, fiber-to-chip coupling and polarization management are discussed as other important issues in the field of integrated photonics. Concerning polarization management, stepped waveguide approach will be introduced as the most promising approach for SOI and III-V substrates and designs based on this structure reported in literature are reproduced and inaccuracies are pointed out and corrected accordingly. Also regarding fiber-to-chip coupling, a critical appraisal of the most recent proposed structures for edge coupling will be offered and the results will be reproduced by simulation tools. At the end, based on detailed comparisons, the most encouraging approach with low insertion loss and easy fabrication steps is introduced and novel platform for easy butt coupling single mode fibers to the coupler structure is proposed.

The work presented in this thesis is motivated by the ultimate goal of realizing a fully integrated quantum optical circuit (IQOC), based on a III-V semiconductor, specifically gallium arsenide (GaAs), in a planar architecture with embedded indium arsenide (InAs) quantum dots as single photon sources. Technological challenges involved with achieving a scalable quantum photonic circuit are addressed through the design, development and testing of controllable on-chip nano-photonic elements, such as nanobeam photonic crystal filters and electro-mechanical actuators. The research into both of these types of devices presented here represents the first work of this kind that has been carried out in the LDSD group at the University of Sheffield. The majority of the measurements that have been undertaken and which are presented here are of an optical spectroscopic nature. An on-chip optical filter based on a one-dimensional photonic crystal structure has been modelled and demonstrated experimentally. Such devices can be integrated with other circuit elements in order to achieve a purely electrically driven IQOC. Tuning the resonant wavelength of the device in order to attain control over the filtering parameters has also been investigated. Control over the splitting ratio of an on-chip optical beam splitter operating at the single photon level has been achieved through an electro-mechanical cantilever based system for the first time on the GaAs platform. This technology, which can be used for switching and phase shifting, now paves the way towards the physical realization of reconfigurable IQOCs. Other more efficient and versatile electro-mechanical systems that could be used to provide greater control over a variety of optical circuit elements, such as filters and beam splitters, have also been investigated experimentally. Comb-drive actuators, which are well established on silicon based platforms, have been developed for use in the GaAs based quantum optical architecture.

Thesis: S.M., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2017.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 85-91).
With recent advances in integrated single-photon sources and quantum memories, onchip integration of high-performance single-photon detectors becomes increasingly important. The superconducting nanowire single-photon detector (SNSPD) is the leading single-photon counting technology for quantum information processing. Among various waveguide materials, aluminum nitride (AlN) is a promising candidate because of its exceptionally wide bandgap, and intrinsic piezoelectric and electro-optic properties. In this Master's thesis, we developed a complete fabrication process for making high-performance niobium nitride SNSPDs on AlN, and demonstrated their integration with AlN photonic waveguides. The detectors fabricated on this new substrate material have demonstrated saturated detection efficiency from visible to near-IR, sub-60-ps timing jitter, and ~6 ns reset time. This work will contribute towards building a fully integrated quantum photonic processor.
by Di Zhu.
S.M.

Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2016.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 55-59).
Graphene is a 2D material recognized for its extremely high mobility and novel optoelectronic properties. In this thesis, we argue in favor of integrating graphene as an active optoelectronic material alongside optical waveguides on the back-end of CMOS ICs for photonic links in access network and computing applications. We describe a simple fabrication process which can accommodate both graphene modulators and photodetectors on almost any waveguide platform. We use this process to fabricate such devices on silicon waveguides and provide preliminary measurements. Finally, we discuss further research opportunities to improve graphene modulators and detectors to the point of being a competitive technology.
by Jordan Goldstein.
M. Eng.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.
Includes bibliographical references (p. 173-184).
The development of future electronic-photonic integrated circuits (EPIC) based on silicon technology critically depends on the availability of CMOS-compatible high-speed modulators that enable the interaction of electronic and optical signals. This thesis investigates electrically driven Mach-Zehnder modulators based on high-index contrast silicon waveguide technology and electronic carrier injection. Modulators based on four different structures are investigated: the forward-biased PiN diode with and without lifetime reduction, the reverse-biased PIN/PN diode and a metal-oxide-semiconductor (MOS) structure. These devices are compared with each other in terms of achievable performance. A modulator based on the forward-biased PIN diode with lifetime reduction is designed to reach 34GHz bandwidth and a low figure of merit V -. L = 0.6V - cm using a carrier lifetime reduction and a graded doping profile. A bandwidth of 1-2GHz has been demonstrated so far which is considerably smaller than the design bandwidth due to high series resistance. Modulators based on the forward-biased PIN structure without lifetime reduction have a low figure of merit, very low voltage and extremely low power consumption in the low frequency regime.
(cont.) The measurements demonstrate a RF power consumption of 100mW for 25% modulation depth and a figure of merit of V, - L = 0.28V - cm at frequencies up to 10GHz. A pre-compensation technique, using a high pass filter which consists of a parallel resistor and capacitor, extends the modulator bandwidth from 100MHz to 5GHz experimentally. Further it is shown that, modulators based on the reverse-biased structure can in principle reach very high speed, up to 40-80GHz in design but it's difficult to reduce V, - L values close to or even below 1V - cm and the necessary drive voltage is higher than the voltage provided by the CMOS technology. For the measured bandwidth of the fabricated devices so far only 1-2GHz has been demonstrated. This discrepancy is caused by the RC delay due to the experimental setup and high contact resistance. Finally, the performance of the modulator based on the metal-on-semiconductor (MOS) structure is analyzed. Furthermore, an electrically driven Mach-Zehnder waveguide modulator based on a high-index contrast silicon split-ridge waveguide (SRW) technology and electronic carrier injection is proposed.
(cont.) The excellent optical and carrier confinement possible in high-index contrast waveguide devices, together with the forward biased operation and the good thermal heat sinking due to the silicon slab close to the waveguide, enables high speed modulation with small signal modulation bandwidths beyond 20GHz, a V, times length figure of merit of V, - L = 0.5Vcm and an insertion loss of about 5.3 dB. Finally, all-optical switches based on optical carrier-injection in high index contrast Si/Si02 split-ridge-waveguide (SRW) couplers are proposed. The waveguide devices are suitable for the construction of low-loss optical switch matrices as well as fast optical switching. These devices exhibit robustness against fabrication tolerances, improved heat sinking, good carrier confinement and high uniformity in transmission over the entire C-band of optical communications in contrast to comparable devices based on buried or ridge waveguides. A reasonably low electrical switching power of 1-10mW is predicted for switching frequencies in the 1MHz-1GHz range. Faster switching speed can be achieved by carrier lifetime reduction.
by Fuwan Gan.
Ph.D.

This thesis investigates ytterbium doped tantalum pentoxide as a material system for realising waveguide lasers on silicon substrate, as a basis to provide the next generation of mass-producible, low-cost planar devices with many interlocking photonic circuits for multi-functionality. Numerical modelling of symmetrical rib waveguide in Ta2O5 was carried out finding an optimum waveguide design for a near-circular mode profile with maximum confinement of light within the core with various etch depths and rib widths. A numerical study investigating the feasibility of integrated Kerr lens elements for future mode-locking was carried out, predicting that a Kerr lens slab with a length of 20 μm with input and out waveguides was able to achieve a 9% modulation depth for input intensity of 6 GW/m2. Thin films were fabricated by RF magnetron sputtering onto a silicon substrate with 2.5 μm silica layer from a powder pressed Yb:Ta2O5 target, with shallow rib waveguides realised using photolithography and ion beam milling. The excited-state lifetime of Yb:Ta2O5 was measured to be 0.25 ± 0.03 ms, and peak emission and absorption cross-sections were determined to be 2.9 ± 0.7×10-20 cm2 and 2.75 ± 0.2×10-20 cm2 respectively, with the fluorescence spectrum giving a broadband emission from 990 nm to 1090 nm. Finally a 10.8 mm long waveguide laser in Ta2O5 doped with ≈ 6.2×1020 Yb atoms/cm3 of ytterbium oxide was demonstrated with a laser cavity formed from a combination of high reflective mirrors with output couplers or reflections from the bare end-facets with Fresnel reflectivity of 12%. In a 5.4 μm wide waveguide, lasing was observed between 1015 nm and 1030 nm when end-pumped with a 977 nm laser diode with the highest output power of 25 mW at a wavelength of 1025 nm with an absorbed pump power of 120 mW for a cavity formed by a high reflector mirror and a bare end-facet at the output. In this case, the absorbed pump power threshold and slope efficiency were measured to be ≈ 30 mW and ≈ 26% respectively. The results presented in this thesis demonstrate that tantalum pentoxide has great potential for mass-producible, integrated optical circuits on silicon using conventional CMOS fabrication technologies.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.
Includes bibliographical references (p. 185-188).
The silicon electronic-photonic integrated circuit (EPIC) has emerged as a promising technology to break through the interconnect bottlenecks in telecommunications and on-chip interconnects. High performance photonic modulators and photodetectors compatible with Si complimentary metal oxide semiconductor (CMOS) devices are indispensable to achieve this goal. A photonic modulator generates optical "1" and "0" signals by switching the light on and off, while a photodetector converts the optical signals to electrical ones so that they can be processed by a CMOS circuit. Due to its compatibility with Si CMOS processing and adequate optoelectric properties, epitaxial GeSi material has been considered as a promising candidate to achieve this goal. This thesis investigates epitaxial GeSi photodetectors and electro-absorption (EA) modulators integrated with high index contrast Si(core)/Si02(cladding) waveguides to form an EPIC circuit on a Si platform with CMOS compatibility. Tensile strain is introduced into the GeSi material to enhance its optoelectronic properties. The effect of tensile strain on the band structure of Ge is systematically studied, and the deformation potential constants of Ge are derived from the experimental results with relatively high accuracy.
(cont.) Methods to engineer the tensile strain in Ge are demonstrated. Tensile strain in small, selectively grown Ge mesas and stripes with at least one dimension <<10 jim is also investigated. The results are instructive to design selectively grown GeSi EA modulators and photodetectors integrated with Si/SiO2 waveguides. Free-space coupled Ge photodetectors on Si are fabricated with significantly improved performance in the L band (1561-1620nm) of telecommunications as a result of strain engineering. We have demonstrated a selectively grown Ge photodetector on a Si platform with a bandwidth of 8.5 GHz and a high responsivity over a broad wavelength range of 650-1605 nm. Full responsivity was achieved at 0 bias and full bandwidth was obtained at 1 V reverse bias, compatible with the requirement of Si ultra-large scale integrated circuits (ULSI). The GeSi EA modulator is based on Franz-Keldysh (FK) effect, where the electric field shifts the direct band edge of the GeSi material and significantly enhances its absorption coefficient in the weakly absorbing regime. Therefore, by modulating the electric field in the GeSi material, we can modulate the intensity of the light of a certain range of wavelength that passes through the GeSi material. A strain-enhanced FK effect in tensile strained epitaxial Ge material is demonstrated.
(cont.) A waveguide-integrated GeSi EA modulator with 4.8 dB insertion loss, 9.8 dB extinction ratio and a bandwidth >50 GHz has been designed with the material composition and device structure optimized for operations around 1550 nm. The same material and device structure can be also used for waveguide-integrated photodetectors with a responsivity of 1.1 A/W at 1550 nm and a bandwidth >35 GHz. A method to monolithically integrate GeSi modulators, photodetectors and Si/SiO2 waveguides is proposed and the expected performance is evaluated. Waveguide-integrated GeSi photodetectors and EA modulators are fabricated on a standard 180 nm CMOS production line based on the design. We demonstrate a waveguide-integrated GeSi photodetector with a responsivity of 1.0 A/W at 1518 nm and a bandwidth >4.5 GHz, as well as a GeSi EA modulator with an extinction ratio of -0.3 dB. While the device performance of the EA modulator is far from ideal due to fabrication issues, the preliminary results demonstrate the feasibility of the electronic-photonic integration on a Si platform with GeSi modulator and detector devices. The problems in this first device processing are identified, and solutions are proposed and partially tested. The device performance could be greatly enhanced with improved processing technique.
by Jifeng Liu.
Ph.D.

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2004.
Includes bibliographical references (leaf 69).
Waveguide bends, in the (In,Ga)(As,P) material system, have been simulated, fabricated and tested. A process is developed for waveguides of 1 [micro]m through 7[micro]m widths. Waveguides containing S-bends of varying bending radii as well as resonator bends were examined. Inconsistent measurement results were obtained. Improved measurement methods have been suggested.
by Sarah J. Rodriguez.
S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2007.
Includes bibliographical references (p. 123-129).
The drive towards photonic integrated circuits (PIC) necessitates the development of new devices and materials capable of achieving miniaturization and integration on a CMOS compatible platform. Optical switching: fast modulation and add-drop switches, key components in a PIC, were investigated. A MEMS-based approach was utilized to control switching in planar ring resonator waveguide structures. A switch extinction ratio of 15 dB, switch speed of 60 is and 1 mW operating power were demonstrated. A metal-insulator transition material, V02, was identified as a material with potential for enhancing the switch speed with speeds in excess of gigahertz rates with minimal device footprint. Fundamental material transport properties and nonstoichiometry in VO2 were characterized. Nonstoichiometry as high as 5% was measured. A Frenkel defect model was used to describe the behavior in V02 in which vanadium interstitials were attributed to be the dominant ionic defect in the reducing regime. Frozen-in vanadium interstitials, acting as shallow donors lying 20 meV below the conduction band in the semiconducting phase, enhance the low temperature conductivity and free carrier concentration.
(cont.) VO2 was shown to exhibit an activated mobility in its semiconducting and "metallic" phases with room temperature mobility estimated to be 5x10-2 cm2/Vs. Electrical switch contrasts of as high as -5000 and optical extinction ratios of approximately 16 dB were demonstrated. Free carrier absorption due to shallow donor vanadium interstitials was identified as a dominant absorption mechanism at near-IR wavelengths. Control of the degree of nonstoichiometry was shown to influence the near-IR absorption effects. To address the need for an integrated fast switch for data encoding, a thin film electro-optic (E-O) modulator, based on barium titanate (BaTiO3) or barium titanate-strontium titanate (SrTiO3) superlattices, was developed. Mach-Zhender E-O modulators were designed, fabricated with CMOS compatible processing steps and tested. Effective electro-optic values as high as 73pmN/V, 2.5 times better performance compared to commercial bulk LiNbO3 technology was demonstrated, with device area less than 30,000 [mu]2.
by Dilan Anuradha Seneviratne.
Ph.D.

The emergence of integrated quantum photonics is revolutionising the field of photonic quantum information science and technology. Quantum photonic waveguide platforms, capable of integrating single photon sources, quantum optical circuits and single photon detectors on semiconductor chips by exploring mature micro- or nano-fabrication technology, greatly promise unprecedented complexity, miniaturisation, scalability and robustness for advanced quantum information applications, including quantum communication, sensing, simulation, machine learning and computing. This thesis is to continually enlarge the scope of integrated quantum photonics technology by developing new materials, devices and systems for new functionalities including generation, manipulation, transmission, distribution, interconversion and measurement of photonic quantum states. Gallium arsenide waveguide quantum circuits are first developed to manipulate photons, demonstrating two-photon quantum interference in integrated beamsplitters and manipulation of photon number entanglement in optical interferometers utilising the linear electro-optic effect of gallium arsenide. We also demonstrate a chip-to-chip quantum photonic interconnect, by demonstrating high-fidelity entanglement generation, manipulation, transmission, distribution and measurement across two separate integrated silicon quantum photonic chips. A highfidelity interconversion of path and polarisation encoding preserves coherence across the full interconnected chip-to-chip system. This would allows quantum information encoding, processing and analysing on chips and quantum information transmission and distribution across chips, towards the multi-chip and multi-core quantum systems. We report on-chip generation of high-purity orbital angular momentum states and the fast-speed reconfigurability and switch-ability using an ultra-compact integrated silicon microring resonator embedded with angular diffractive gratings. Quantitive and qualitative measurements are performed to analyse the orbital angular momentum states from the chip. This might allow a high-capacity quantum interconnectivity of free space and integrated quantum circuits for many quantum information prototypes. This thesis demonstrates the capabilities of on-chip encoding, controlling, transferring and analysing quantum states in photon's path, polarisation and spatial modes degrees of freedom, providing a new generation of integrated quantum photonics toolbox for future quantum information technology.

Esta tesis doctoral tiene como objetivo el diseño y la implementación de dispositivos ópticos novedosos capaces de realizar tareas de procesado de señales de rediofrecuencia, concretamente en las bandas de microondas y milimétricas, explotando para ello efectos de luz lenta que tienen lugar sobre algunos medios físicos que presentan características especiales. Con este propósito, se han investigado estructuras basadas en tecnología de semiconductor en guiaonda, además de estructuras de naturaleza resonante sobre circuitos en silicio y compuestos híbridos fabricados con materiales activos pertenecientes a los grupos III-V sobre silicio. En concreto, se han prouestos diferentes circuitos ópticos capaces de desarrollar tareas propias de desfasador y retardadeo verdadero de banda ancha para señales de radiofrecuncia. El comportamiento de dichos circuitos ópticos bajo estudio se ha caracterizado mediante modelado teórico, quedando éstos adecuadamente validados a través de resultados experimentales. En primer lugar, se han llevado a cabo estudios concernientes a la degradación producida por ruido en estructuras desfasadores formadas por amplificadores ópticos de semiconductor. Como resultado, se ha propuesto una nueva estructura que ha revertido en un rendimiento optimizado en términos de ruido sin que ello suponga una alteración en su funcionnalidad básica como desfasador. Esta estructura desfasadora ha sido el elemento clave en el ensamblado de un filtro elimina banda sintonizable. En segundo lugar, se han utilizado diferentes configuraciones basadas en anillos de silicio con dimensiones micrométricas para el desarrollo e implementación de diferentes procesadores de señal, tales como filtros reconfigurables y sintonizables y retardadores multicanal. Concretamente, se ha introducido un nuevo concepto inspirado en la técnica conocida como SCT, cuyo beneficio redunda en un aumento considerable del ancho de banda útil de las señales de radiofrecuencia a procesar gracias a
Lloret Soler, JA. (2012). Slow Light Effects in Photonic Integrated Circuits with Application to Microwave Photonics [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/16472
Palancia

Multiport beam splitter is a new research topic in quantum communication. To improve the security system, the dimension/capacity of quantum communication should increase. In this thesis, design, simulation and methodology of NXN multiport beam splitter on a photonic integrated circuit is explained. Photonic integrated circuit has more advantages than other optical components to design a multiport beam splitter. Multiport beam splitter on a photonic chip gives configuration stability, a compact prototype for future quantum network.

Les oscillateurs de référence de haute pureté sont actuellement utilisés dans un grand nombre d’applications allant du contrôle de fréquence aux horloges pour les radars, les GPS et l’espace... Les tendances actuelles dans ce domaine requièrent des architectures miniaturisées avec la génération de signaux directement dans la gamme de fréquences d’intérêt, autour de quelques GHz. Récemment, de nouvelles architectures basées sur les principes de l’optomécanique ont vu le jour dans ce but. De tels oscillateurs optomécanique génèrent non seulement des signaux hyperfréquences directement dans la gamme de fréquences GHz avec éventuellement un faible bruit de phase, mais permettent également un degré élevé d'intégration sur puce. Ce travail de thèse s'inscrit dans cette démarche. L’oscillateur optomécanique étudié se compose de cavités à cristaux photoniques suspendues couplées à des guides d’ondes silicium sur isolant intégrés dans une architecture tridimensionnelle. Ces cavités abritent des modes optiques fortement confinés autour de 1550nm et des modes mécaniques dans le GHz. De plus, ces structures présentent un recouvrement spatial entre phonon et photon élevé. Il en résulte un couplage optomécanique amélioré. Cette force de couplage optomécanique améliorée est ici sondée optiquement sur des structures à cristaux photoniques de conception optimisée. Ces cavités sont réalisées dans des matériaux semi-conducteurs III-V dont la piézoélectricité nous permet d'intégrer des outils supplémentaires pour sonder et contrôler les vibrations mécaniques via un pilotage capacitif, piézoélectrique ou acoustique. Ce contrôle total des modes mécaniques et de l’interaction optomécanique ouvre la voie à la mise en œuvre de circuits intégrés pour le verrouillage par injection et des boucles de rétroaction permettant de réduire le bruit de phase de l’oscillateur
High purity reference oscillators are currently used in a wide variety of frequency control and timing applications including radar, GPS, space... Current trends in such fields call for miniaturized architectures with direct signal generation in the frequency range of interest, around few GHz. Recently, novel optomechanically-enhanced architectures have emerged with this purpose. Such optomechanically-driven oscillators not only generate microwave signals directly in the GHz frequency range with possibly low phase noise but also are amenable to a high degree of integration on single chip settings. This PhD work falls within this scope. The optomechanically-driven oscillator under study consists of suspended photonic crystal cavities coupled to integrated silicon-on-insulator waveguides in a three-dimensional architecture. These cavities harbor highly-confined optical modes around 1,55 µm and mechanical modes in the GHz and most importantly, feature a high phonon-photon spatial overlap, all resulting in an enhanced optomechanical coupling. This enhanced optomechanical coupling strength is here probed optically on photonic crystal structures with optimized design. These cavities are hosted in III-V semiconductor materials whose piezoelectricity enable us to integrate additional tools for probing and controlling mechanical vibrations via capacitive, piezoelectric or acoustic driving. This full control over the mechanical modes and optomechanical interaction, paves the way towards the implementation of integrated injection locking circuits of feedback loops for reducing the phase noise of the oscillator

The prolific rate at which advances in photonics have been made in recent years has increased the need for accurate and efficient computer aided design tools. New device technologies and material systems mean the designer is faced with many more degrees of freedom with which to optimise a design. Because of this versatile techniques that yield results accurately and quickly are foremost in the designers mind. Throughout this work a well proven technique, the Spectral Index (SI) method is extended and generalised to a wide variety design situations of practical importance. The design of a novel Silicon Germanium based device was used to prove the suitability of an iterative design methodology in developing and optimising practical waveguiding components. The novel development of the SI method for the accurate analysis of waveguide losses is then presented further extending its suitability to the analysis and design of rectangular rib waveguides. Following this the generalisation of the SI method to structures of non-rectangular cross-section is presented allowing for the analysis of a wider range of optical rib waveguides. A novel implementation of the SI method is then developed for the analysis of the whispering gallery class of resonant modes supported by cylindrical dielectric disc and ring structures, allowing for the characterisation of the optical properties of this important class of devices. A 3D circuit analysis technique based upon a robust implementation of the SI method in its complex form is developed that allows for the characterisation of any waveguide system that may be represented by a number of discrete waveguide components. Finally the SI method is generalised to the full 3D exact analysis of optical waveguiding structures.

[EN] Microwave photonics (MWP) is a well-established research field that investigates the use of photonic technologies to generate, distribute, process and analyze RF waveforms in the optical domain. Despite its great potential to solve long-standing problems faced by both the microwave and electronics industries, MWP systems are bulky, expensive and consume a lot of power. Integrated microwave photonics (IMWP) is an emerging area of research that promises to alleviate most of these drawbacks through the use of photonic integrated circuits (PIC). In this work, we have aimed at further closing the gap between the worlds of MWP and integrated optics. In particular, we have focused on the design and experimental characterization of PICs with reconfigurable, ring-assisted Mach-Zehnder interferometer filters (RAMZI), and demonstrated its potential use in different IMWP applications. These filters consist of a symmetric MZI loaded with ring resonators, which are coupled to the MZI branches by different optical couplers. The contributions of this thesis can be split into two sections. In the first one, we demonstrate integrated optical couplers and reflectors with variable power splitting and reflections ratios. These exploit the well-known properties of tapered multimode interference couplers (MMI), and their inherent robustness makes them highly suitable for the implementation of both RAMZI and reflective filters. Besides, we study in detail the impact of manufacturing deviations in the performance of a 4x4 MMI-based 90º hybrid, which is a fundamental building block in coherent optical communication systems. In the second section, we demonstrate the use of integrated RAMZI filters for three different IMWP applications, including instantaneous frequency measurement (IFM), direct detection of frequency-modulated signals in a MWP link, as well as in tunable, coherent MWP filters. A theoretical analysis of the limits and trade-offs that exist in photonics-based IFM systems is also provided. Even though these are early proof-of-concept experiments, we hope that further technological developments in the field will finally turn MWP into a commercial reality.
[ES] La fotónica de microondas (MWP) es un campo de investigación que estudia el uso de tecnologías ópticas para generar, distribuir, procesar y analizar señales de RF. A pesar de su gran potencial para resolver algunos de los problemas a los que se enfrentan las industrias electrónica y de microondas, estos sistemas son voluminosos, caros y consumen mucha potencia. La fotónica de microondas integrada (IMWP) es un área emergente que promete solucionar todos estos inconvenientes a través de la utilización de circuitos ópticos integrados (PIC). En esta tesis, hemos pretendido avanzar un poco más en el acercamiento entre estas dos disciplinas. En concreto, nos hemos centrado en el diseño y caracterización experimental de PICs con filtros reconfigurables basados en interferómetros Mach-Zehnder cargados con anillos (RAMZI), y demostrado su potencial uso en diferentes aplicaciones de IMWP. Los filtros RAMZI están hecho básicamente de un MZI simétrico cargado con anillos, los cuales a su vez se acoplan a las ramas del interferómetro a través de distintos acopladores ópticos. Las contribuciones de este trabajo se pueden dividir en dos partes. En la primera, hemos demostrado acopladores y reflectores ópticos integrados con coeficientes de acoplo y reflexión variables. Éstos explotan las propiedades de los acopladores por interferencia multimodal (MMI), y su robustez les hace muy atractivos para la implementación de filtros RAMZI y de tipo reflectivo. Además, hemos analizado el impacto que las tolerancias de fabricación tienen en el rendimiento de un híbrido óptico de 90º basado en un MMI 4x4, el cual es un elemento fundamental en los sistemas de comunicaciones ópticas coherentes. En la segunda parte, hemos demostrado el uso de filtros RAMZI en tres aplicaciones distintas de IMWP. En concreto, hemos utilizado dichos filtros para implementar sistemas de medida de frecuencia instantánea (IFM), detección directa de señales moduladas en frecuencia para enlaces fotónicos, así como en filtros coherentes y sintonizables de MWP. También hemos desarrollado un análisis teórico de las limitaciones y problemas que existen en los sistemas IFM. A pesar de que todos los experimentos realizados han consistido en prototipos para una prueba de concepto, esperamos que futuros avances tecnológicos permitan que la fotónica de microondas se convierta algún día en una realidad comercial.
[CAT] La fotònica de microones (MWP) és un camp d'investigació que estudia l'ús de tecnologies òptiques per a generar, distribuir, processar y analitzar senyals de radiofreqüència. A pesar del seu gran potencial per a resoldre alguns dels problemes als que s'enfronten les indústries electrònica i de microones, estos sistemes son voluminosos, cars i consumixen molta potència. La fotònica de microones integrada (IMWP) és un àrea emergent que promet solucionar tots estos inconvenients a través de la utilització de circuits òptics integrats (PIC). En esta tesi, hem pretés avançar un poc més en l'acostament entre estes dos disciplines. En concret, ens hem centrat en el disseny i caracterització experimental de PICs amb filtres reconfigurables basats en interferòmetres Mach-Zehnder carregats amb anells (RAMZI), i demostrat el seu potencial en diferents aplicacions d' IMWP. Els filtres RAMZI estan fets bàsicament d'un MZI simètric carregat amb anells, els quals, al seu torn, s'acoblen a les branques del interferòmetre a través de distints acobladors òptics. Les contribucions d'este treball es poden dividir en dos parts. En la primera, hem demostrat acobladors i reflectors òptics integrats amb coeficients de transmissió i reflexió variables. Estos exploten les propietats dels acobladors per interferència multimodal (MMI), i la seua robustesa els fa molt atractius per a la implementació de filtres RAMZI i de tipo reflectiu. A més a més, hem analitzat l'impacte que les toleràncies de fabricació tenen en el rendiment d'un híbrid òptic de 90 graus basat en un MMI 4x4, el qual és un element fonamental en els sistemes de comunicacions òptiques coherents. En la segona part, hem demostrat l'ús de filtres RAMZI en tres aplicacions diferents de IMWP. En concret, hem utilitzat estos filtres per a implementar sistemes de mesura de freqüència instantània (IFM), detecció directa de senyals modulades en freqüència per a enllaços fotònics, així com en filtres coherents i sintonitzables de MWP. També hem desenvolupat una anàlisi teòrica de les limitacions i problemes que existixen en els sistemes IFM. A pesar de que tots els experiments realitzats han consistit en prototips per a una prova de concepte, esperem que futurs avanços tecnològics permeten que la fotònica de microones es convertisca algun dia en una realitat comercial.
Sánchez Fandiño, JA. (2016). Integrated Optical Filters for Microwave Photonic Applications [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/67690
TESIS

Integrated microwave photonics changes the scaling laws of information and communication systems offering architectural choices that combine photonics with electronics to optimize performance, power, footprint and cost. Application Specific Photonic Integrated Circuits, where particular circuits/chips are designed to optimally perform particular functionalities, require a considerable number of design and fabrication iterations leading to long-development times and costly implementations. A different approach inspired by electronic Field Programmable Gate Arrays is the programmable Microwave Photonic processor, where a common hardware implemented by the combination of microwave, photonic and electronic subsystems, realizes different functionalities through programming. Here, we propose the first-ever generic-purpose Microwave Photonic processor concept and architecture. This versatile processor requires a powerful end-to-end field-based analytical model to optimally configure all their subsystems as well as to evaluate their performance in terms of the radiofrequency gain, noise and dynamic range. Therefore, we develop a generic model for integrated Microwave Photonics systems. The key element of the processor is the reconfigurable optical core. It requires high flexibility and versatility to enable reconfigurable interconnections between subsystems as well as the synthesis of photonic integrated circuits. For this element, we focus on a 2-dimensional photonic waveguide mesh based on the interconnection of tunable couplers. Within the framework of this Thesis, we have proposed two novel interconnection schemes, aiming for a mesh design with a high level of versatility. Focusing on the hexagonal waveguide mesh, we explore the synthesis of a high variety of photonic integrated circuits and particular Microwave Photonics applications that can potentially be performed on a single hardware. In addition, we report the first-ever demonstration of such reconfigurable waveguide mesh in silicon. We demonstrate a world-record number of functionalities on a single photonic integrated circuit enabling over 30 different functionalities from the 100 that could be potentially obtained with a simple seven hexagonal cell structure. The resulting device can be applied to different fields including communications, chemical and biomedical sensing, signal processing, multiprocessor networks as well as quantum information systems. Our work is an important step towards this paradigm and sets the base for a new era of generic-purpose photonic integrated systems.
Los dispositivos integrados de fotónica de microondas ofrecen soluciones optimizadas para los sistemas de información y comunicación. Generalmente, están compuestos por diferentes arquitecturas en las que subsistemas ópticos y electrónicos se integran para optimizar las prestaciones, el consumo, el tamaño y el coste del dispositivo final. Hasta ahora, los circuitos/chips de propósito específico se han diseñado para proporcionar una funcionalidad concreta, requiriendo así un número considerable de iteraciones entre las etapas de diseño, fabricación y medida, que origina tiempos de desarrollo largos y costes demasiado elevados. Una alternativa, inspirada por las FPGA (del inglés Field Programmable Gate Array), es el procesador fotónico programable. Este dispositivo combina la integración de subsistemas de microondas, ópticos y electrónicos para realizar, mediante la programación de los mismos y sus interconexiones, diferentes funcionalidades. En este trabajo, proponemos por primera vez el concepto del procesador de propósito general, así como su arquitectura. Además, con el fin de diseñar, optimizar y evaluar las prestaciones básicas del dispositivo, hemos desarrollado un modelo analítico extremo a extremo basado en las componentes del campo electromagnético. El modelo desarrollado proporciona como resultado la ganancia, el ruido y el rango dinámico global para distintas configuraciones de modulación y detección, en función de los subsistemas y su configuración. El elemento principal del procesador es su núcleo óptico reconfigurable. Éste requiere un alto grado de flexibilidad y versatilidad para reconfigurar las interconexiones entre los distintos subsistemas y para sintetizar los circuitos para el procesado óptico. Para este subsistema, proponemos el diseño de guías de onda reconfigurables para la creación de mallados bidimensionales. En el marco de esta tesis, hemos propuesto dos nuevos nodos de interconexión óptica para mallas reconfigurables, con el objetivo de obtener un mayor grado de versatilidad. Una vez escogida la malla hexagonal para el núcleo del procesador, hemos analizado la configuración de un gran número de circuitos fotónicos integrados y de funcionalidades de fotónica de microondas. El trabajo se ha completado con la demonstración de la primera malla reconfigurable integrada en un chip de silicio, demostrando además la síntesis de 30 de las 100 funcionalidades que potencialmente se pueden obtener con la malla diseñada compuesta de 7 celdas hexagonales. Este hecho supone un record frente a los sistemas de propósito específico. El sistema puede aplicarse en diferentes campos como las comunicaciones, los sensores químicos y biomédicos, el procesado de señales, la gestión y procesamiento de redes y los sistemas de información cuánticos. El conjunto del trabajo realizado representa un paso importante en la evolución de este paradigma, y sienta las bases para una nueva era de dispositivos fotónicos de propósito general.
Els dispositius integrats de Fotònica de Microones oferixen solucions optimitzades per als sistemes d'informació i comunicació. Generalment, estan compostos per diferents arquitectures en què subsistemes òptics i electrònics s'integren per a optimitzar les prestacions, el consum, la grandària i el cost del dispositiu final. Fins ara, els circuits/xips de propòsit específic s'han dissenyat per a proporcionar una funcionalitat concreta, requerint així un nombre considerable d'iteracions entre les etapes de disseny, fabricació i mesura, que origina temps de desenrotllament llargs i costos massa elevats. Una alternativa, inspirada per les FPGA (de l'anglés Field Programmable Gate Array), és el processador fotònic programable. Este dispositiu combina la integració de subsistemes de microones, òptics i electrònics per a realitzar, per mitjà de la programació dels mateixos i les seues interconnexions, diferents funcionalitats. En este treball proposem per primera vegada el concepte del processador de propòsit general, així com la seua arquitectura. A més, a fi de dissenyar, optimitzar i avaluar les prestacions bàsiques del dispositiu, hem desenrotllat un model analític extrem a extrem basat en els components del camp electromagnètic. El model desenrotllat proporciona com resultat el guany, el soroll i el rang dinàmic global per a distintes configuracions de modulació i detecció, en funció dels subsistemes i la seua configuració. L'element principal del processador és el seu nucli òptic reconfigurable. Este requerix un alt grau de flexibilitat i versatilitat per a reconfigurar les interconnexions entre els distints subsistemes i per a sintetitzar els circuits per al processat òptic. Per a este subsistema, proposem el disseny de guies d'onda reconfigurables per a la creació de mallats bidimensionals. En el marc d'esta tesi, hem proposat dos nous nodes d'interconnexió òptica per a malles reconfigurables, amb l'objectiu d'obtindre un major grau de versatilitat. Una vegada triada la malla hexagonal per al nucli del processador, hem analitzat la configuració d'un gran nombre de circuits fotónicos integrats i de funcionalitats de fotónica de microones. El treball s'ha completat amb la demostració de la primera malla reconfigurable integrada en un xip de silici, demostrant a més la síntesi de 30 de les 100 funcionalitats que potencialment es poden obtindre amb la malla dissenyada composta de 7 cèl·lules hexagonals. Este fet suposa un rècord enfront dels sistemes de propòsit específic. El sistema pot aplicarse en diferents camps com les comunicacions, els sensors químics i biomèdics, el processat de senyals, la gestió i processament de xarxes i els sistemes d'informació quàntics. El conjunt del treball realitzat representa un pas important en l'evolució d'este paradigma, i assenta les bases per a una nova era de dispositius fotónicos de propòsit general.
Pérez López, D. (2017). Integrated Microwave Photonic Processors using Waveguide Mesh Cores [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/91232
TESIS

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2018.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 93-107).
Quantum computation and communication systems exploit quantum mechanical effects to surpass their classical counterparts in certain applications. However, while proof-of-principle experimental demonstrations have been performed, these are limited to a handful of nodes with limited - and often immutable - connectivity. Here we demonstrate an integrated platform for solid state quantum information processing. Pre-characterized solid state quantum nodes (nitrogen vacancy centers in diamond nanophotonic structures) are placed into a photonic integrated circuit which allows for low-loss and phase-stable collection, routing, and detection of photons as well as on-chip state manipulation and classical control. Moreover, the fabrication of high-quality photonic resonators in diamond allows for the increased emission and collection rates of photons coherent with the spin state. These two advances promise an on-chip entanglement rate much larger than the decoherence rate, allowing the creation and maintenance of cluster states for quantum computation.
by Sara Lambert Mouradian.
Ph. D.

La photonique sur silicium permet de palier au faible rendement et la consommation énergétique élevée des liens télécoms exploitant les câbles à paires torsadées ou les câbles coaxiaux. Cette technologie offre une versatilité exceptionnelle, de nouvelles fonctionnalités et des performances accrues pour les communications à haut-débit, les systèmes d’interconnexions optiques à courte portée et le déploiement de liaisons optiques d’une puce à une autre, d’une carte à une autre, ou d’un rack à un autre (datacom). Le silicium est un matériau semi-conducteur très efficace pour le guidage de la lumière, notamment en raison du fort contraste d’indice avec la silice. Cependant, sa bande interdite indirecte ne permet pas une émission radiative efficace. La réalisation de lasers repose donc sur des technologies hybrides de collage ou de report du matériau actif III- V (wafer-bonding, flip-chip) sur le silicium passif. Cependant, cette intégration hétérogène présente des inconvénients comme par exemple un coût élevé et une évolutivité limitée. Les lasers hybrides sur silicium sont aussi plus sensibles aux réflexions parasites provenant des transitions des différentes interfaces passives/actives. Un moyen permettant de surmonter ces inconvénients consiste à faire croître directement le matériau III-V sur le silicium. Dans ce contexte, les lasers à boîtes quantiques utilisant des atomes semi-conducteurs comme milieu de gain sont des candidats très prometteurs en raison de leur compacité, de leur grande stabilité thermique et d’une tolérance accrue aux défauts structuraux. Certaines applications comme les systèmes cohérents, les futures horloges atomiques intégrées sur puces et les radars où la sensibilité aux bruits de fréquence et d’intensité influe fortement le taux d’erreur binaire requièrent l’utilisation d’émetteurs optiques à très faible bruit. Dans une première partie, cette thèse révèle le potentiel de lasers à boîtes quantiques InAs/InP présentant une largeur de raie spectrale intrinsèque de 80 kHz et un bruit relatif d’intensité inférieur à -150 dB/Hz. A cet effet, il est montré qu’un faible couplage vertical entre les états liés est plus approprié pour une réduction du bruit d’intensité notamment grâce à la suppression du bruit de porteurs associée à l’état excité. Dans une deuxième partie, les propriétés dynamiques et non- linéaires des lasers à boîtes quantiques directement épitaxiés sur silicium sont étudiées. Comme susmentionné, les lasers intégrés de manière hétérogène sur le silicium sont plus sensibles aux réflexions parasites. Combinées à une rétroaction optique externe, la stabilité du laser peut s’en trouver fortement affectée. Sachant qu’il n’existe pas à ce jour d’isolateurs optiques intégrés sur puce ayant un taux d’isolation suffisant, le développement d’émetteurs insensibles aux rétroactions est un objectif majeur. Cette thèse présente notamment un résultat de transmission sans erreur à partir d’un laser à boîtes quantique directement épitaxié sur silicium soumis à une modulation externe à 10 Gb/s ainsi qu’à une rétroaction optique maximale de 100%. Cette insensibilité aux réflexions résulte de plusieurs propriétés remarquables comme un facteur d’élargissement spectral proche de zéro, un facteur d’amortissement élevé, un fort contraste entre les seuils d’émission des états liés, et une durée de vie des porteurs plus courte. Ces résultats permettent d’envisager le développement de futurs circuits intégrés photoniques sur silicium à haute performance et fonctionnant sans isolateur optique
Silicon photonics have been introduced to overcome low efficiency and high energy consumption of telecom links using twisted pairs or coaxial cables. This technology provides novel functionality and high performance for applications in high speed communication systems, short reach optical interconnects, and the deployment of optical links from chipto-chip, board-to-board or rack-to-rack (datacom). Silicon is known as a very efficient semiconductor material for waveguiding light in particular owing to the strong index contrast with silica. However, the indirect bandgap of silicon makes light emission from silicon inefficient, and other techniques such as wafer- or flipchip bonding must be investigated if light emission is to be realized. The drawbacks of such heterogeneous integration concentrate on the high cost and the limited scalability. Lasers heterogeneously integrated on silicon are also more sensitive to optical reflections originating from the transition between passive/active interfaces. The best way to overcome these drawbacks is to move on to direct epitaxial growth of IIIV materials on silicon for photonics integration. In this context, quantum dot lasers using semiconductor atoms as a gain medium are ideal because they enable smaller devices, amplification with large thermal stability and high tolerance to epitaxial defects. Ultra-low noise optical transmitters are required not only for the coherent systems but also for future chipscale atomic clocks and radar related applications because of the sensitivity to the frequency noise and intensity noise can strongly affect the bit error rates. To this end, the first part of the thesis reports an intrinsic spectral linewidth as low as 80 kHz and a relative intensity noise less than - 150 dB/Hz in InAs/InP quantum dot lasers. In particular, it is shown that a small vertical coupling is more suitable for low intensity noise operation due to the suppression of the carrier noise in the excited state. The second part of the thesis investigates the dynamic and nonlinear properties of epitaxial quantum dot lasers on silicon. As mentioned above, lasers heterogeneously integrated on silicon are more sensitive to parasitic reflections. When combined with external optical feedback, the laser stability can be dramatically affected. As no on-chip optical isolators integrated with lasers and having sufficient isolation ratio exist, the development of feedback insensitive transmitters remains a major objective. This thesis presents an error-free transmission of an epitaxial quantum dot laser on silicon externally modulated at 10 Gb/s and subjected to 100% optical feedback. Such remarkable feedback insensitivity directly results from the near-zero linewidth enhancement factor, the large damping factor, the strong contrast between the ground state and excited states and a shorter carrier lifetime. These results pave the way for future high-performance photonics integrated circuits on silicon operating without optical isolators

Ces trois années de thèse balayent la conception, la fabrication et la caractérisation de lasers III V sur silicium à 1.31 µm pour les data-communications. Le design des sources englobe notamment l’optimisation du couplage entre l’empilement III V et le silicium, effectué grâce à un taper adiabatique, ainsi que l’étude de la cavité laser inscrite, comme le taper, dans le silicium. Trois types de cavités à base de réseaux ont été étudiées: les cavités à contre-réaction distribuée (DFB pour distributed feedback), celles à réseaux de Bragg distribuées (DBR pour distributed Bragg reflector) et enfin celles à réseaux de Bragg échantillonnées (SGDBR pour sampled-grating DBR). Deux solutions ont été abordées concernant les lasers DFB: le réseau, inscrit dans le guide silicium sous la zone de gain, est soit gravé au-dessus du guide Si, soit sur les côtés. La seconde possibilité, appelée ‘DFB lasers couplés latéralement’, simplifie la fabrication et élargit les possibilités de design.Les lasers DFB fabriqués sont très prometteurs en terme de puissance (avec jusque 20 mW dans le guide) ainsi que pour leur pureté spectrale (avec une différence de plus de 50 dB entre le mode principal et le mode suivant). Une accordabilité spectrale de plus de 27 nm a été obtenue en continu avec les lasers SGDBR tout en conservant une très bonne pureté spectrale et une puissance de plus de 7 mW dans le guide
This 3 years work covers the design, the process and the characterization of III-V on silicon lasers at 1.31 µm for datacommunication applications. In particular, the design part includes the optimization of the coupling between III V and Si using adiabatic tapers as well as the laser cavity, which is formed within the Si. Three types of lasers were studied, all of them based on cavities which consist of gratings: distributed feedback (DFB) lasers, distributed Bragg reflector (DBR) lasers and finally sampled-grating DBR (SGDBR) lasers. Regarding the DFB lasers, two solutions have been chosen: the grating is either etched on top or on the edges of the Si waveguide to form so called vertically or laterally coupled DFB lasers. The latter type, quite uncommon among hybrid III V on Si technologies, simplifies the process fabrication and broadens the designs possibilities.Not only the lasers demonstrated show high output powers (~20 mW in the waveguides) but also very good spectral purities (with a side mode suppression ratio higher than 50 dB), especially for the DFB ones. The SGDBR devices turn out to be continuously tunable over a wavelength range higher than 27 nm with a good spectral purity as well and an output power higher than 7 mW in the waveguide with great opportunities of improvement