Дисертації з теми "Highly nonlinear fibre"
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Camerlingo, Angela. "New optical fibre based technologies and their application in highly nonlinear systems." Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/183175/.
Повний текст джерелаZambo, Abou'ou Marcelle Nina. "Instabilité modulationnelle et concept de réservoir de photons dans les fibres optiques à très forte non linéarité." Thesis, Dijon, 2011. http://www.theses.fr/2011DIJOS045/document.
Повний текст джерелаThis thesis considers modulational instability (MI) in optical fibers that have both a strong non-linearity and strong absorption coefficient. We carry out a comparative analysis of the performance of several major classes of silica- and non-silica glass fibers, on their ability to generate MI sidebands with a minimum of pump power, and over the shortest distance possible. Chalcogenide glass fibers appear at first sight as being the most competitive, but a careful examination reveals that their spectra are altered by a phenomenon of frequency drift of the MI sidebands, caused by a strong depletion of the pump. We have then developed a method which allows to suppress frequency drifts in MI processes in fibers having strong absorption parameters. The fundamental idea of this method, that we called "the photon reservoir method", is to create in the fiber, by an appropriate adjustment of the second-order and fourthorder dispersion coefficients, a photon reservoir which supplies (in situ) the MI process by continually providing the equivalent of the amount of photons destroyed by absorption during the propagation. We have demonstrated the effectiveness of the method of photon reservoir on MI processes, in scalarand vector configurations, using glass fibers endowed with extremely high nonlinear parameters. This method constitutes a decisive step forward in the development of highly competitive devices for optical frequency generation
Ortigosa, Blanch Arturo. "Highly birefringent photonic crystal fibres : linear and nonlinear effects." Thesis, University of Bath, 2002. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.760818.
Повний текст джерелаYusoff, Zulfadzli. "Applications of highly nonlinear holey fibres in optical communications." Thesis, University of Southampton, 2004. https://eprints.soton.ac.uk/15465/.
Повний текст джерелаFung, Wai-lam. "A novel all-optical wavelength exchange in highly nonlinear fiber." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39558782.
Повний текст джерела馮慧琳 and Wai-lam Fung. "A novel all-optical wavelength exchange in highly nonlinear fiber." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39558782.
Повний текст джерелаEttabib, Mohamed A. "All-optical signal processing in novel highly nonlinear fibres and waveguides." Thesis, University of Southampton, 2014. https://eprints.soton.ac.uk/368583/.
Повний текст джерелаZhang, Jian. "Nonlinear methods for distributed sensing in high birefringence optical fibres." Thesis, King's College London (University of London), 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300417.
Повний текст джерелаMalik, Rohit. "Experimental investigation of high-power continuous-wave fiber optical parametric amplifiers and oscillators." Thesis, Swansea University, 2010. https://cronfa.swan.ac.uk/Record/cronfa42491.
Повний текст джерелаKim, Jong-Kook. "Investigation of High-Nonlinearity Glass Fibers for Potential Applications in Ultrafast Nonlinear Fiber Devices." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/28569.
Повний текст джерелаPh. D.
Goel, Nitin Kumar. "Development of "Core-Suction" Technique for Fabrication of Highly Doped Fibers for Optical Amplification and Characterization of Optical Fibers for Raman Amplification." Diss., Virginia Tech, 2005. http://hdl.handle.net/10919/29302.
Повний текст джерелаPh. D.
Luo, Linqing. "Time-frequency localisation of distributed Brillouin Optical Time Domain Reflectometry." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/274568.
Повний текст джерелаHori, Takashi, Norihiko Nishizawa, Hiroyuki Nagai, Makoto Yoshida, and Toshio Goto. "Electronically controlled high-speed wavelength-tunable femtosecond soliton pulse generation using acoustooptic modulator." IEEE, 2001. http://hdl.handle.net/2237/6768.
Повний текст джерелаLeigh, Matthew. "HIGH POWER PULSED FIBER LASER SOURCES AND THEIR USE IN TERAHERTZ GENERATION ." Diss., The University of Arizona, 2008. http://hdl.handle.net/10150/193797.
Повний текст джерелаBordonaro, Giancarlo Giuseppe. "Nonlinear System Identification of Physical Parameters for Damage Prognosis and Localization in Structures." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/30019.
Повний текст джерелаPh. D.
Takayanagi, Jun, Norihiko Nishizawa, Hiroyuki Nagai, Makoto Yoshida, and Toshio Goto. "Generation of high-power femtosecond pulse and octave-spanning ultrabroad supercontinuum using all-fiber system." IEEE, 2005. http://hdl.handle.net/2237/6770.
Повний текст джерелаParsa, Shahrzad. "High-power fiber-laser-pumped picosecond nonlinear optical sources from the near- to mid-infrared." Doctoral thesis, Universitat Politècnica de Catalunya, 2018. http://hdl.handle.net/10803/620786.
Повний текст джерелаLas fuentes coherentes de picosegundos ultrarrápidos en el rango espectral de infrarrojo cercano a infrarrojo medio (IR) son de gran interés para una amplia variedad de aplicaciones tales como pump-probe espectroscopia, la teledetección, la fotobiología y las nuevas técnicas de upconversion imaging. La óptica no lineal, y en particular las técnicas de conversión de frecuencia no lineal, ofrecen un enfoque eficiente y eficaz para la realización de fuentes que emiten tales radiaciones, ya que hoy en día, las fuentes basadas en la conversión de frecuencia no lineal son fuentes viables y fiables de emisión de radiaciones láser con amplia sintonía de longitud de onda y escalabilidad de potencia, sin necesidad de refrigeración criogénica. En esta tesis, hemos demostrado fuentes de picosegundos de alta potencia y alta tasa de repetición basadas en procesos de conversión de frecuencia no lineales a través de osciladores ópticos paramétricos (OPO) y generación de frecuencias de diferencia (DFG) para cubrir la región de longitud de onda de IR cercano a IR medio del espectro electromagnético. Hemos desarrollado una fuente de picosegundos estable, de alta tasa de repetición, rápidamente sintonizable, basado en un cristal PPKTP con períodos de rejilla diseñados en forma de abanico. El OPO, es bombeado sincrónicamente por un mode-locked láser de fibra de Yb, doblado en frecuencia para generar verde a 532 nm, que proporciona radiación estable y de alta potencia rápidamente sintonizable de 749-962 nm en el signal y de 1189-1838 nm en el idler, a temperatura ambiente. Además, hemos demostrado lo que creemos que es la primera fuente de picosegundos sintonizable con alta tasa de repetición basada en el cristal OP-GaP en el IR medio. Usando una DFG de un solo paso entre un mode-locked láser de fibra de Yb a 1064 nm y la salida ajustable de un OPO de picosegundo basado en un cristal de MgO:sPPLT bombeado sincrónicamente por el mismo láser, la fuente generó radiación sintonizable de 3040-3132 nm en el medio-IR a la velocidad de repetición de ~80 MHz, con buena calidad de haz. Además, también presentamos el primer OPO de picosegundos de alta potencia y buena calidad de haz, con resonancia del idler, basado en un cristal MgO:PPLN de rejilla múltiple sintonizable a lo largo de 2100-4000 nm en el IR medio. El OPO proporcionó hasta 3.5 W de radiación de IR medio con valores de M2 mejores que 1.8 tanto en dirección horizontal como vertical
Ben, braham Fatma. "Contribution à l’étude théorique et expérimentale d’un oscillateur laser fonctionnant en régime impulsionnel dans les bandes spectrales C et L." Thesis, Angers, 2018. http://www.theses.fr/2018ANGE0025.
Повний текст джерелаThis work deals with the development of a fiber laser generating high energy and width tunable square pulses and high-energy giant pulses. First, we have developed a numerical model to study the generation of rectangular pulses in a double amplifier fiber laser. The objective is to study the impact of the non-linear effect induced by the microstructured optical fiber on the control of the square pulse duration. A set of laser parameters allowed us to generate high energy square pulses in the dissipative soliton resonance (DSR) regime. In addition, several experiments have been set up to optimize the generation of the DSR pulse in terms of energy and duration. Experimentally, high energy giant pulses from a passively mode-locked fiber ring laser coupled to a long external cavity are obtained. This allowed us to generate a wide range of pulse duration of μs at a low repetition rate in cavities using artificial saturable absorbers
Chaitanya, Kumar Suddapalli. "High-power, fiber-laser-pumped optical parametric oscillators from the visible to mid-infrared." Doctoral thesis, Universitat Politècnica de Catalunya, 2012. http://hdl.handle.net/10803/83528.
Повний текст джерелаFuentes coherentes de luz continua y de alta potencia en el infrarrojo-medio (mid-IR) son de gran interés por su aplicación en la detección de gases, detección remota y la observación de imágenes. Estas aplicaciones requieren un ancho de banda amplio para evidenciar las características que ofrece la absorción de una gran variedad de especies moleculares, particularmente en la región “finger print” del mid-IR. Por otra parte, fuentes altamente energéticas con pulsos que posean estructuras peculiares en rangos específicos de longitud de onda en el mid-IR, entre 6-6.5 m. , prometen características únicas para nuevas aplicaciones en cirugía. Osciladores ópticos paramétricos (OPOs) constituyen fuentes de luz versátiles y apropiadas para todas las aplicaciones mencionadas anteriormente. La longitud de En el régimen ultrarápido, hemos demostrado una nueva técnica de interferometría para la optimización absoluta de la potencia de salida de un oscilador óptico con una cavidad de anillo. Como demostración de principio, implementamos, por primera vez, un OPO de picosegundos en el mid-IR basado en MgO:PPLN con una cavidad de anillo bombeado por un láser de fibra de Yb. Además, hemos desarrollado un nuevo OPO de alta energía en el mid-IR basado en el material nolineal CSP. Esto representa la primera demostración de un OPO compacto de alta repetición sincrónicamente bombeado por un láser de estado sólido a 1064 nm generando pulsos de milijulios en el rango espectral 6-6.5 m. Esta radiación es importante para aplicaciones en cirugía. Adicionalmente, hemos demostrado una fuente verde, 532 nm, basada en láseres de fibra. Esta radiación se obtiene por medio de la generación de segundo harmónico (SHG) en un paso individual en MgO:sPPLT. Esto representa una nueva alternativa de bombeo para los láseres de Ti:sapphire que los harán compactos en el futuro. Los esfuerzos para mejorar la eficiencia de segundo harmónico resultaron en el desarrollo de un novedoso esquema que utiliza múltiples cristales y permite eficiencias de SHG de paso individual del 56%. Este esquema es general y simple y puede ser implementado para cualquier longitud de onda. onda de un OPO puede ser sintonizada en regiones amplias del espectro cambiando la temperatura del cristal no-lineal, el ángulo de ajuste de fase o, al considerar materiales cuasi ajuste de fase (QPM), cambiando el periodo de red. En esta tesis, hemos demostrado una gran variedad de OPOs en el mid-IR en régimen continuo y de pulsos de picosegundo. Estos OPOs han sido bombeados por láseres de fibra permitiendo un diseño compacto y resistente. En el régimen de emisión continua, hemos implementado un OPO de alta potencia basado en MgO:PPLN bombeado por un láser de fibra. Este OPO es sintonízable en el rango 1506-1945 nm correspondiente al infrarrojo-cercano y en el rango 2304-3615 nm correspondiente al mid-IR. Esta capacidad de sintonización se logra al sobrepasar eficientemente los efectos térmicos optimizando el acoplamiento de salida. Materiales nuevos como el MgO:sPPLT, con propiedades ópticas y térmicas mejoradas para la generación de radiación continua en el mid-IR han sido estudiados. Utilizando las propiedades ajuste de la fase extendió del MgO:sPPLT, fuentes continuas de alta potencia con un gran ancho de banda en el infrarrojo-medio también han sido implementadas.
Baselt, Tobias, Christopher Taudt, Bryan Nelsen, Andrés Fabián Lasagni та Peter Hartmann. "All-fiber supercontinuum source with flat, high power spectral density in the range between 1.1 μm to 1.4 μm based on an Yb3+ doped nonlinear photonic crystal fiber". SPIE, 2017. https://tud.qucosa.de/id/qucosa%3A35120.
Повний текст джерелаRydberg, Sara. "Rare Earth elements in optical materials and design of high power ytterbium fiber laser for frequency doubling using nonlinear ppKTP crystal." Thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-36138.
Повний текст джерелаEl, Mansouri Ibrahim. "Sources impulsionnelles picosecondes tout optique à très haut débit : applications aux télécommunications optiques." Thesis, Dijon, 2013. http://www.theses.fr/2013DIJOS064/document.
Повний текст джерелаThis thesis presents the work carried out on the realization of fibered 40-GHz picosecond optical pulse sources in the telecommunications C-band. In the first part, we present a numerical and experimental study of the generation of 40-GHz pulse trains thanks to the nonlinear compression of an initial beat-signal by multiple Four-Wave Mixing process. Enhanced temporal stability is achieved by generating the sinusoidal beating thanks to a Mach-Zehnder modulator driven at its zero-transmission working point. In order to improve the quality of the generated pulses, we also demonstrate the suppression of stimulated Brillouin back-scattering by inserting several optical isolators into the compression line. In the next part, we present the generation of low duty-cycle pulse trains by using a nonlinear compressor line based on 4 segments of fiber. The generated pulse trains have been encoded and then multiplexed to achieve a high bit rate signal (160 Gb/s). In the last part, we present the technology transfer steps of this optical source, such as creating a prototype of the source, prior art search and market research
Semaan, Georges. "Soliton dynamics in fiber lasers : from dissipative soliton to dissipative soliton resonance." Thesis, Angers, 2017. http://www.theses.fr/2017ANGE0029/document.
Повний текст джерелаIn this thesis, we investigate experimentally the generation of high energy nanosecond tunable square pulses and high output power ultrashort pulses in fiber lasers. First, since pulse dynamics are dominated by the interaction of the fiber's cubic Kerr nonlinearity and chromatic dispersion with an intensity-discriminating mechanism referred to as a saturable absorber, the stability of a harmonic mode-locked distribution is studied by external injection of a continuous wave. Finally, we implemented nanomaterial based saturable absorbers in fiber laser configuration to generate ultrashort pulses with high average output power. Different techniques of achieving such components are explicitly detailed: ultrashort pulse generation in ring cavities where graphene and topological insulators are deposited on optical tapers to form a saturable absorber
Neumann, Niels. "Signal processing with optical delay line filters for high bit rate transmission systems." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-64036.
Повний текст джерелаOver the course of the past decades, the global communication system has become a central part of people's everyday lives. Optical communication systems are the technological basis for this development. Only fibers can provide the huge bandwidth that is required. Where the fiber could be regarded as a flat channel for the first optical transmission systems wavelength multiplexing and increasing line rates made it necessary to take more and more physical effects into account. When the line rates are increased to 40 Gbit/s and higher static chromatic dispersion compensation is not enough. The modulation format's intrinsic tolerance for dispersion decreases quadratically with the symbol rate. Thus, environmentally induced chromatic dispersion fluctuations may exceed the dispersion tolerance of the modulation formats. This makes an adaptive dispersion compensation necessary implying also the need for a monitoring scheme to steer the adaptive compensator. Legacy links that are CD-compensated by DCFs can be upgraded with residual dispersion compensators to make them ready for high speed transmission. Optical compensation is independent from the line rate. Hence, increasing the data rates is inherently supported. Optical compensators can be built WDM ready compensating multiple channels at once. The book deals with optical delay line filters as one class of optical compensators. The filter synthesis of such delay line filters is addressed. The connection between optical filters and digital FIR filters with complex coefficients that are used in conjunction with coherent detection could be shown. Iterative and analytical methods that produce the coefficients for dispersion (and also dispersion slope) compensating filters are researched. As important as the compensation of dispersion is the estimation of the dispersion of a signal. Using delay line filters, the vestigial sidebands of a signal can be used to measure the dispersion. Alternatively, nonlinear detection can be used to estimate the pulse broadening which is caused mainly by dispersion. With dispersion compensation and dispersion monitoring, dispersion compensators can be adapted to the signal's impairment. Special properties of the filter in conjunction with an analytical description can be used to provide a fast and reliable control algorithm for setting the filter to a given dispersion and centering it on a signal. Finally, prototypes of such fiber optic chromatic dispersion and dispersion slope compensation filters were manufactured and characterized. The device and system characterization of the prototypes is presented and discussed
Munasinghe, Hashan Tilanka. "Soft glass optical fibres for telecommunications applications." Thesis, 2015. http://hdl.handle.net/2440/100712.
Повний текст джерелаThesis (Ph.D.) -- University of Adelaide, School of Physical Sciences, 2015.
Zhang, Hui. "Lumped fiber Raman amplifiers with highly nonlinear fiber." Thesis, 2005. http://spectrum.library.concordia.ca/8713/1/MR14289.pdf.
Повний текст джерелаCheng-Yu, Wang. "All-Optical XOR Operation Generation Using Nonlinear Polarization Rotation in a Single Highly Nonlinear Fiber." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0016-1303200709301426.
Повний текст джерелаWang, Cheng-Yu, and 王振宇. "All-Optical XOR Operation Generation Using Nonlinear Polarization Rotation in a Single Highly Nonlinear Fiber." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/98092753692883379196.
Повний текст джерела國立清華大學
光電工程研究所
94
In recent days, the demand for high speed photonic communication networks was much larger little by little. A key building block in many areas of optical signal processing is just the all-optical XOR logic gate. For the fiber-based reconfigurable high-speed optical network, an all-fiber solution for the XOR gate is highly desirable with the added advantages of (i) no need for OE/EO conversion, (ii) ultrafast nonlinear response time (~2-4 fs) of Kerr effect in the fiber, and (iii) excellent fiber compatibility. These advantages make highly nonlinear fiber devices to be attracting considerable attention in the aspects of many researches. In this thesis, we try to simulate to achieve all-optical XOR logic function by using polarization rotation in a single HNLF at 10 Gb/s and 20 Gb/s. Thus, we accomplished signal-processing in all-optical domain. Besides, we also try to tune some parameters, for example, the selections of the input power and wavelength of lasers and the length and fiber loss of the highly nonlinear fiber (HNLF), to investigate the influence on the performance of the all-optical XOR logic gate. The results of this research will reveal the fact that these parameters indeed play an important role in the performance of all-optical XOR logic gate by using polarization rotation in a single HNLF. As a result, we will understand how to use these appropriate parameters of all-optical XOR logic gate in order to get the better performance of it based on the concept of using a highly nonlinear fiber. These investigations and demonstrations will be useful expectedly in the field of high speed photonic communication networks for the next generation.
Kuo, Chih-yuan, and 郭志遠. "The studies of supercontinuum source utilizing highly-nonlinear-fiber in an erbium-doped-fiber ring cavity." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/71873472621077520625.
Повний текст джерела國立高雄師範大學
光電與通訊工程學系
102
The main argument of this thesis is that delay fiber and power density in the cavity make effect on nonlinear polarization rotation and stimulating Raman scattering in the architecture of supercontinuum source. This supercontinuum source is based on an erbium-doped fiber laser and Nonlinear Polarization Rotation intensity dependent loss. The both effects of nonlinear polarization rotation and stimulating Raman scattering could be cross analyzed by changing type and length of delay fibers. Furthermore, vary the optical power density in cavity is used to investigate the threshold of the nonlinear effects. The different length of 1-m, 10-m, and 100-m of highly nonlinear fibers in the ring cavity couldn’t make the laser reach the threshold level of nonlinear effects. Because of the fusing losses and the delaying fiber losses, the total optical power losses in the system can’t activate the HNLFs to generate the supercontinuum lasing in the fiber ring cavity.
HAO-YU, PAN, and 潘浩宇. "The studies of supercontinuum generation in highly nonlinear fiber using tunable bandwidth seed signal." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/55419399386277498469.
Повний текст джерела國立高雄師範大學
光電與通訊工程學系
102
We produce supercontinuum source by using different bandwidth signals as the seed signal, and to study performance of supercontinuum source by different bandwidth seed signals for HNLF. Most commonly supercontinuum source was stressed ultra-short pulse laser system, we propose a tunable broadband source as the seed signals, and adjust different bandwidth seed signal into the HNLF, we also utilize SRS and SPM effect to shift energy. In addition we discussed the different seed signal for the nonlinear effects by adjusting the cavity length and polarization state, and change the erbium-doped fiber amplifier pump power for the nonlinear effects. The last we analysis the supercontinuum sources of the HNLFs with different lengths and dispersion values. The experimental results show that when using the broadband seed signal, the spectral is broader, and also show that when using the longer highly nonlinear fiber, which has broader spectral, and the overall flatness is better. When used the 1Km HNLF has best results, the spectra range of supercontinuum source is from 1180nm to 1700nm, which is above 518nm, the optimum flatness of supercontinuum is 30dB.
Chen, Wei-Chih, and 陳韋志. "Supercontinuum generation in highly nonlinear fiber by well-defined laser pulses at 1550 nm." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/67s3kq.
Повний текст джерела國立交通大學
照明與能源光電研究所
106
We report the generation of supercontinuum by well-defined laser pulses at 1550 nm through a piece of 1-meter highly nonlinear fiber. The laser pulses at 19 MHz repetition rate were amplified to an average power of 5.22 W by the pre-amplifier and the booster, and the pulse duration is 23.1 ps. The supercontinuum has an optical spectrum spanning from 1020 to 2153 nm, and its average power is 3.34 W.
Spillane, Sean Michael. "Fiber-Coupled Ultra-High-Q Microresonators for Nonlinear and Quantum Optics." Thesis, 2004. https://thesis.library.caltech.edu/2348/1/thesis.pdf.
Повний текст джерелаThe ability to confine optical energy in small volumes for long periods of time is desirable for a number of applications, ranging from photonics and nonlinear optics, to fundamental studies in quantum electrodynamics. Whispering-gallery-mode microresonators are a promising cavity to study, due to the ability to obtain quality factors exceeding 100 million in micron-scale volumes. This thesis investigates the suitability of ultra-high-quality factor silica microresonators (both silica microspheres and silica toroidal microresonators) for nonlinear and quantum optics. Crucial to the actual use of these structures is the ability to efficiently excite and extract optical energy. The first part of this thesis investigates the ability to achieve near lossless coupling between a fiber-taper waveguide and a silica microresonator. It is shown that a coupling ideality (which is the fraction of energy coupled into the desired fiber mode) in excess of 99.97% is possible, meaning that optical energy can be coupled both to and from the optical resonator with near perfect efficiency.
Using tapered fibers, low threshold stimulated Raman scattering is observed in both silica microspheres and silica microtoroids at record low incident pump powers below 100 microwatts, much lower than previous devices. High conversion efficiencies (>35%) are also realized. Furthermore, the conditions for optimized performance of both stimulated Raman scattering and parametric oscillation in a microcavity are described.
Lastly, the suitability of toroidal microcavities for strong coupling cavity quantum electrodynamics is investigated. Numerical modeling of the optical modes demonstrates a significant reduction of modal volume with respect to spherical cavities, while retaining high quality factors. The extra degree of freedom of toroid microcavities can be used to achieve improved strong-coupling characteristics, and numerical results for atom-cavity coupling strength, critical atom number and critical photon numbers for cesium are calculated and shown to exceed values currently possible using Fabry-Perot cavities. Modeling predicts atom-cavity coupling rates exceeding 700 MHz and critical atom numbers approaching 10⁻⁷.
Fernandes, Marco André Tavares. "Digital pre-distortion for 5G transmission over high-capacity optical fronthaul fiber links." Master's thesis, 2019. http://hdl.handle.net/10773/29568.
Повний текст джерелаA nova geração de comunicações rádio traz muitos desafios para o transporte destes mesmos sinais. Enquanto que é exigida maior capacidade, os requisitos para complexidade, custo, consumo de potência e latência são mais estritos. Esta dissertação explora a possibilidade de usar transmissão analógica de sinais rádio sobre fibra em redes de acesso centralizadas. _E proposto e estudado o uso de transmissores óticos de baixo custo baseados em transmissores SFP adaptados para transportar sinais analógicos. A performance dos transmissores é caracterizada experimentalmente com sinais 4G e 5G. Os campos de estudo desta dissertação incluem o impacto da frequência da portadora, a potência RF transmitida, a potência ótica recebida e o comprimento da fibra. Adicionalmente, os benefícios de usar um polinômio com memória para compensação não linear são avaliados. Esta compensação não linear permite operações 5G de elevada performance obtendo um EVM inferior a 3.5% para sinais na região de frequências 1 com 100 MHz de largura de banda, o que é inferior aos limites estabelecidos pelo 3GPP para transmissão 256QAM. Adicionalmente uma redução de EVM de 5.7% para 5.4% é verificada quando se transmite um sinal 5G FR2 com 400 MHz de largura de banda por 20 km de fibra.
Mestrado em Engenharia Eletrónica e Telecomunicações
Tavassoli, Vahid. "High capacity phase/amplitude modulated optical communication systems and nonlinear inter-channel impairments." Thesis, 2012. http://hdl.handle.net/1828/3889.
Повний текст джерелаGraduate
Ben, Braham Fatma. "Contribution à l’étude théorique et expérimentale d’un oscillateur laser fonctionnant en régime impulsionnel dans les bandes spectrales C et L." Thesis, 2018. http://www.theses.fr/2018ANGE0025/document.
Повний текст джерелаThis work deals with the development of a fiber laser generating high energy and width tunable square pulses and high-energy giant pulses. First, we have developed a numerical model to study the generation of rectangular pulses in a double amplifier fiber laser. The objective is to study the impact of the non-linear effect induced by the microstructured optical fiber on the control of the square pulse duration. A set of laser parameters allowed us to generate high energy square pulses in the dissipative soliton resonance (DSR) regime. In addition, several experiments have been set up to optimize the generation of the DSR pulse in terms of energy and duration. Experimentally, high energy giant pulses from a passively mode-locked fiber ring laser coupled to a long external cavity are obtained. This allowed us to generate a wide range of pulse duration of μs at a low repetition rate in cavities using artificial saturable absorbers
Neumann, Niels. "Signal processing with optical delay line filters for high bit rate transmission systems." Doctoral thesis, 2010. https://tud.qucosa.de/id/qucosa%3A25472.
Повний текст джерелаOver the course of the past decades, the global communication system has become a central part of people's everyday lives. Optical communication systems are the technological basis for this development. Only fibers can provide the huge bandwidth that is required. Where the fiber could be regarded as a flat channel for the first optical transmission systems wavelength multiplexing and increasing line rates made it necessary to take more and more physical effects into account. When the line rates are increased to 40 Gbit/s and higher static chromatic dispersion compensation is not enough. The modulation format's intrinsic tolerance for dispersion decreases quadratically with the symbol rate. Thus, environmentally induced chromatic dispersion fluctuations may exceed the dispersion tolerance of the modulation formats. This makes an adaptive dispersion compensation necessary implying also the need for a monitoring scheme to steer the adaptive compensator. Legacy links that are CD-compensated by DCFs can be upgraded with residual dispersion compensators to make them ready for high speed transmission. Optical compensation is independent from the line rate. Hence, increasing the data rates is inherently supported. Optical compensators can be built WDM ready compensating multiple channels at once. The book deals with optical delay line filters as one class of optical compensators. The filter synthesis of such delay line filters is addressed. The connection between optical filters and digital FIR filters with complex coefficients that are used in conjunction with coherent detection could be shown. Iterative and analytical methods that produce the coefficients for dispersion (and also dispersion slope) compensating filters are researched. As important as the compensation of dispersion is the estimation of the dispersion of a signal. Using delay line filters, the vestigial sidebands of a signal can be used to measure the dispersion. Alternatively, nonlinear detection can be used to estimate the pulse broadening which is caused mainly by dispersion. With dispersion compensation and dispersion monitoring, dispersion compensators can be adapted to the signal's impairment. Special properties of the filter in conjunction with an analytical description can be used to provide a fast and reliable control algorithm for setting the filter to a given dispersion and centering it on a signal. Finally, prototypes of such fiber optic chromatic dispersion and dispersion slope compensation filters were manufactured and characterized. The device and system characterization of the prototypes is presented and discussed.