Dissertations / Theses on the topic 'Tunable Fiber Laser'
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1
Beaudoin, Gerald R. "Fiber optic based tunable diode laser gas detector." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0013/MQ60101.pdf.
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Fadel, Hicham Joseph. "Tunable erbium-doped fiber ring laser using an intra-cavity filter." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/1050.
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Linear tuning the frequency of an erbium-doped fiber ring laser using both a Fabry-Perot filter and an electro-optic tunable filter has been experimentally demonstrated. The rate of frequency change is determined by monitoring the fringes produced by laser light transmitted through a fiber Fabry-Perot interferometer. The fiber ring laser has been tuned over a 50 nm spectral range when using the Fabry-Perot filter and a tuning rate of 16480 nm/s has been achieved. The spectral width of the laser is 0.049 nm and the nearest sidelobe to the main peak is more than 30 dB below the central lobe. When the electro-optic tunable filter is used, a spectral range of 11 nm is reached. The spectral width is 2.33 nm and is in close agreement with the filter theoretical results. The sidelobe to main peak difference is around 13 dB.
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Guesmi, Khmaies. "Etude d’un laser à fibre microstructurée en forme de huit et développement de sources à 1.6 μm." Thesis, Angers, 2015. http://www.theses.fr/2015ANGE0030/document.
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Les travaux de recherche, rapportés dans ce manuscrit, portent sur l’étude d’un laser à fibre en forme de huit et le développement de sources à 1.6 µm. En premier temps, nous avons étudié la dynamique impulsionnelle d’un laser à fibre micro-structurée en forme de huit. L’objectif est de montrer l’impact des propriétés de la fibre micro-structurée sur le comportement impulsionnel du laser. Nous avons également étudié le phénomène d’hystérésis dans cette cavité. Nos résultats numériques ont permis de démontrer l’universalité de ce phénomène dans les cavités lasers. Autrement, il est indépendant de la technique de verrouillage de modes. En second lieu, nous avons développé une source laser émettant à 1.6 µm à partir d’un amplificateur fonctionnant dans la bande C. La méthode que nous avons explorée est basée sur la gestion des pertes linéaires. L’émission, en continu et en verrouillage de modes, a été démontrée dans deux configurations différentes. Enfin et en se basant sur ce concept, nous avons rapporté des sources accordables sur une large fenêtre spectrale. Nous avons également étudié différentes formes des régimes harmoniques autour de 1.6 µmDuring our research, we are interested in studying of the figure of eight fiber laser based on the microstructured optical fiber and developing a 1.61 µm mode locked fiber laser from a C-band double-clad Er : Yb doped fiber amplifier. In the first step and based on a theoretical model, we have investigated the multi-pulse emission of a microstructured figure-of eight fiber laser operating in passive mode-locking. The proposed laser is mode locked by the nonlinear amplifying loop mirror (NALM). We further study the hysteresis dependence and the number of pulses in steady state as a function of both the small signal gain and the nonlinear coefficient of microstructured fiber. Our results demonstrate that the nonlinear coefficient of microstructured fiber plays a key role in the formation of multi-soliton. In the second step and based on the control of the linear losses of the cavity, we demonstrate the possibility to achieve filter less laser emission above 1.6 μm, from a C-band double-clad Er: Yb doped fiber amplifier, using a figure-of-eight geometry and a unidirectional ring cavity. We also reported a widely tunable mode locked fiber laser and harmonic mode locking of twin and third pulse around 1.61 µm
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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.
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High-power, continuous-wave (cw), mid-infrared (mid-IR) laser sources are of interest
for variety of applications such as trace gas detection and remote sensing, which
require broad spectral coverage to address the most prominent absorption features
of a wide range of molecular species particularly in the mid-IR fingerprint region. On
the other hand, surgical applications require high energy sources with unique pulse
structure at specific wavelength in the mid-IR ranging from 6-6.5 m.
Optical parametric oscillators (OPOs) offer potential sources for all the above
applications. The output wavelengths of a singly-resonant oscillator (SRO) can be
coarsely tuned over wide ranges through the adjustment of the nonlinear crystal
temperature, phase-matching angle or, in the case of quasi-phase-matched (QPM) the first time. The high-energy CSP OPO marked the first demonstration of a
compact, high-repetition-rate OPO synchronously pumped by a master oscillator
power amplifier system at 1064 nm, generating an milli-joule pulses in the 6-6.5 m
spectral range, which is technologically important for surgical applications.
Additionally, we also demonstrated a fiber-based-green source at 532 nm, based
on single-pass second harmonic generation (SHG) in MgO:sPPLT, as an alternative
pump source for Ti:sapphire laser, pointing towards the future, compact fiber-laser
pumped Ti:sapphire lasers. Further efforts to improve the SHG efficiency led to
the development of a novel multi-crystal scheme, enabling single-pass SHG efficiency
as high as 56%. This generic technique is simple and can be implemented at any
wavelength.
materials, the QPM grating period. The combination of SRO with a tunable pump
laser allows the development of uniquely flexible and rapidly tunable class of mid-IR
sources.
In this thesis we have demonstrated several mid-IR OPOs in the cw as well as
ultrafast picosecond regime pumped by fiber-lasers making them compact and robust.
In the cw regime, we developed a high-power, Yb-fiber-laser pumped mid-IR OPO
based on MgO:PPLN spanning 1506-1945 nm in the near-IR and 2304-3615 nm
wavelength range in the mid-IR, efficiently addressing the thermal effects by implementing
the optimum signal output coupling. Novel materials such a MgO:sPPLT,
with better optical and thermal properties for cw mid-IR generation are explored.
High-power broadband, cw mid-IR generation is also demonstrated by using the
extended phase-matching properties of MgO:PPLN.
Further, we also demonstrated a simple, inexpensive and novel interferometric
technique for absolute optimization of output power from a ring optical oscillator.
We deployed a picosecond Yb-fiber-laser pumped mid-IR OPO based on MgO:PPLN
in ring cavity configuration to demonstrate this proof-of-principle experiment forFuentes 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.
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Sabra, Mostafa. "Développement de lasers à fibres thulium bi-fréquences à impulsions synchrones pour la réalisation de sources Térahertz." Thesis, Limoges, 2019. http://www.theses.fr/2019LIMO0118.
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Dans le cadre d’un projet collaboratif entre le laboratoire XLIM (UMR 7252 du CNRS et de l'Université de Limoges) et le laboratoire de recherche IPHT situé à Jena en Allemagne, mon projet de thèse consiste à développer un laser à fibre dopée thulium bi-fréquences largement accordable à impulsions synchrones pour la réalisation d’une source Térahertz puissante et accordable. Basé sur l’utilisation de deux réseaux de Bragg en volume (VBGs) et d’une fibre dopée thulium à double gaine et à maintien de polarisation (diamètre de coeur = 20 μm) fabriquée par la méthode REPUSIL, un laser mono-fréquence et bi-fréquences largement accordable a été réalisé et étudié en régime continu. Une accordabilité de 1nm à 144 nm a été obtenue avec une puissance supérieure à 4,5 W et un bon contraste signal sur bruit (~45 dB) et une largeur spectrale inférieure à 0,1 nm. En régime déclenché, un modulateur acousto-optique (AOM) a été utilisée en espace libre dans la cavité laser afin de générer les impulsions. La fibre à double gaine a été remplacée par une fibre dopée thulium à large coeur (40 μm) appelée FA-LPF pour repousser le seuil d’apparition des effets non-linéaires et travailler avec une fibre courte pour diminuer la durée d’impulsion et augmenter la puissance crête des impulsions obtenues. Une source déclenchée bi-fréquences largement accordable (de 3,8 nm jusqu’à 120nm) a été développée avec une puissance crête supérieure à 8 kW et une durée d’impulsion autour de 26 ns obtenues indépendamment de la valeur de Δλ pour une fréquence de répétition de 1 kHz. Un contraste supérieur à 20 dB a été obtenu limité par les pics parasites générés par le FWM pour les valeurs de Δλ inférieures à 45 nm. La largeur spectrale des raies lasers mesurée à 3 dB du maximum a été inférieure à 0,3 nmAs part of a collaborative project between the XLIM laboratory (UMR 7252 of the CNRS and the University of Limoges) and the IPHT research laboratory located in Jena, Germany, my thesis project consists in the development of a widely tunable dual-wavelength synchronous pulsed thulium doped fiber laser for the realization of an efficient and tunable terahertz source. Based on the use of two volume Bragg gratings (VBGs) and a double-clad, polarization-maintaining thulium doped fiber (core diameter = 20 μm) manufactured by the REPUSIL method, a widely tunable single-wavelength laser and dual-wavelength laser has been realized and studied in continuous regime. A tunability of 1 nm to 144 nm was obtained with a power more than 4.5 W and a good signal-to-noise contrast (~ 45 dB) and a spectral linewidth less than 0.1 nm. In pulse regime, an acousto-optic modulator (AOM) was used in free space in the laser cavity to generate the pulses. The double-clad fiber has been replaced by a large-core thulium doped fiber (40 μm) called FA-LPF to to fend off the threshold of non-linear effects and work with a short fiber to decrease the pulse duration and increase the peak power of the obtained pulses. A widely tunable (from 3.8 nm to 120 nm) Q-switched dual-wavelength synchronous-pulsed thulium-doped fiber laser was developed with a peak power more than 8 kW and a pulse duration around 26 ns obtained independently of the value of Δλ at 1 kHz of repetition rate. A contrast higher than 20 dB was obtained limited by the FWM peaks generated for Δλ values below 45 nm. The spectral linewidth of the laser measured at 3 dB of the maximum was less than 0.3 nm
6
Khanolkar, Ankita Nayankumar. "Effect of Spectral Filtering on Pulse Dynamics of Ultrafast Fiber Oscillators at Normal Dispersion." University of Dayton / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1628171764933755.
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Gloag, Andrew John. "Tunable erbium doped fibre lasers." Thesis, University of Strathclyde, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249838.
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LIMA, ANA PAULA CARDOSO RODRIGUES DE. "WAVELENGTH TUNABLE OPTICAL PULSES GENERATION USING FIBER LASERS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2000. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=7477@1.
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Neste trabalho, descreve-se a geração de pulsos ópticos
curtos com diferentes taxas de repetição, para aplicações
em sistemas de transmissão de sólitons. Para isto foi
desenvolvido um laser a fibra em anel operando na terceira
janela de comunicações ópticas (em 1.55 mm), capaz de
gerar pulsos curtos, utilizando a técnica de mode-locking
ativo. Na configuração empregada o modulador de Mach-
Zehnder, normalmente usado, foi substituído por um laser
DFB, funcionando como modulador de intensidade e, ao mesmo
tempo, como filtro óptico sintonizável. O laser
semicondutor tem seu ganho chaveado através de modulação
direta, levando a cavidade e operar no regime de mode-
locking harmônico. Uma sintonia contínua de comprimentos
de onda pode ser obtida, simplesmente, variando-se a
temperatura do diodo laser. Foram analisados aspectos como
estabilidade, duração e pureza espectral dos pulsos
ópticos emitidos por essa fonte, bem como sua faixa de
sintonia de comprimentos de onda e possíveis taxas de
repetição. Os pulsos ópticos gerados foram transmitidos
através de enlaces ópticos com fibra óptica convencional,
comprovando-se a propagação de sólitons.In this dissertation, it is depicted short optical pulses generation with different repetition rates, for soliton based transmission systems applications. In order to accomplish that, a fiber laser operating at the third window of the optical communication (1.55 um) was developed, capable of generate short pulses, through the active mode-locking technique. Within the current configuration, the Mach-Zehnder modulator, usually employed, was replaced by a DFB laser, running as both an intensity modulator and tunable optical filter. The semiconductor laser was gain switched through direct modulation, leading the cavity to operate on harmonic mode- locking scheme. A continuous wavelength tuning could be achieved by changing the temperature of the diode laser. Several aspects were analyzed, such as stability, duration and spectral purity of the optical pulses generated by this source. The wavelength tuning range and its possible repetition rates were also investigated. The optical pulses were transmitted through standard optical fiber links, demonstrating the propagation of solitons.
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Keszenheimer, James A. "Frequency tunable microchip lasers for coherent sensor applications /." Thesis, Connect to Dissertations & Theses @ Tufts University, 1992.
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Thesis (Ph.D.)--Tufts University, 1992.Submitted to the Dept. of Electrical Engineering. Includes bibliographical references. Access restricted to members of the Tufts University community. Also available via the World Wide Web;
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O, Cochlain Ciaran R. "Tunable erbium doped fibre lasers for lightwave communication systems." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283935.
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Khairuzzaman, Md. "Digitally selected electronically switchable terahertz-over-fibre." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/digitally-selected-electronically-switchable-terahertzoverfibre(7003c9cb-fa46-4933-9348-b1977a446b7f).html.
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The Quantum Cascade Laser (QCL)-based terahertz-over-fibre (ToF) concept combines the strength of QCLs as ultra-wide bandwidth, high speed data sources, with the mature optical fibre technology. In this thesis, for the first time, by fusing multiple technologies, digitally selected, electronically-switchable ToF concept is experimentally demonstrated. Furthermore, the digital mode selection principle and electronic tuning mechanism provided by novel aperiodic distributed feedback (ADFB) multi-band filters are presented. For the development of electronically tunable ADFB lasers, a range of bound-to-continuum and chirped superlattice terahertz (THz) QCLs are measured across the frequency range 2.9 – 4.5 THz. The availability of these active materials allowed rapid assessments of the optimum design parameters for subsequent measurements. First, a range of photonic lattice-engineered lasers operating at 4.4 THz are characterized and key design parameters identified. Following this initial development, full electrical and spectral characterization of ADFB lasers operating at 2.9 THz are presented. The novelty of this work lies in the first-ever successful demonstration of discretely tunable QCLs, operating at six distinct THz frequencies. The ADFB technology was experimentally applied using various device geometries and gain dynamics. Toward this aim, results are presented for a Y coupled QCL architecture, showing that complex on-chip signal manipulation can be extended into the THz regime. In addition, it is demonstrated that ADFB technology provides broadband multi-channel optical filtering for the entire gain bandwidth. It is shown that discrete, purely electronic, tuning of simultaneous dual colour output can be achieved. Multi band optical filter functions derived from ADFB gratings possess highly nonlinear dispersion across the filter bandwidth and are found to modify the gain-induced, driving current-dependent continuous mode tuning. This thesis, therefore, presents a systematic experimental analysis of the dispersion engineered continuous fine-tuning in THz QCLs. In the final two chapters, the thesis presents, for the first time, transmission of tunable THz signals over standard single-mode optical fibre by up converting 2.9 THz QCL radiation via intra-cavity nonlinear mixing with an optical fibre-injected near-infrared (NIR) carrier in the 1.3 µm band. Discrete and continuous tuning technologies, as developed in chapters 3 – 5, are now successfully transferred to THz sidebands on the NIR carrier, extracted via a butt coupled single mode fibre and recorded using an optical spectrum analyzer. The major novel outcome of this thesis is the first demonstration of electronically tunable phase-matched points in a THz plasmon waveguide. The key breakthrough is the experimental confirmation of the photonic band-gap engineering of group velocity of THz signals – as both ‘fast’ and ‘slow’ switchable side bands are observed. Such novel nonlinear up-conversion of spectrally flexible THz signals may open up new possibilities for ultrafast THz telecom frameworks.
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Hori, 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.
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Nishizawa, Norihiko, Youta Ito, and Toshio Goto. "0.78-0.90-μm wavelength-tunable femtosecond soliton pulse generation using photonic crystal fiber." IEEE, 2002. http://hdl.handle.net/2237/6769.
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Nishizawa, Norihiko, and Toshio Goto. "Widely wavelength-tunable ultrashort pulse generation using polarization maintaining optical fibers." IEEE, 2001. http://hdl.handle.net/2237/6864.
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Nishizawa, Norihiko, and Toshio Goto. "Compact system of wavelength-tunable femtosecond soliton pulse generation using optical fibers." IEEE, 1999. http://hdl.handle.net/2237/6767.
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Nishizawa, Norihiko, Ryuji Okamura, and Toshio Goto. "Simultaneous generation of wavelength tunable two-colored femtosecond soliton pulses using optical fibers." IEEE, 1999. http://hdl.handle.net/2237/6771.
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Tieß, Tobias [Verfasser], Hartmut [Gutachter] Bartelt, Stefan [Gutachter] Nolte, and Alain [Gutachter] Villeneuve. "Tunable fiber lasers based on fiber bragg grating arrays and a theta ring cavity / Tobias Tieß ; Gutachter: Hartmut Bartelt, Stefan Nolte, Alain Villeneuve." Jena : Friedrich-Schiller-Universität Jena, 2018. http://d-nb.info/1179090381/34.
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Michel, David Daniel. "Linear-cavity tunable fibre lasers employing an Opto-VLSI processor and a MEMS-based device." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2012. https://ro.ecu.edu.au/theses/520.
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This thesis proposes and demonstrates experimentally two novel linear-cavity tunable fibre lasers employing an erbium-doped fibre (EDF) in conjunction with an Opto- VLSI processor and a MEMS-based device for wavelength selection. The Opto-VLSI processor and the MEMS-based device along with an optical collimator, a Bragg grating plate and an optical lens, enable the realisation of an optical filter for continuous tuning of wavelengths over the amplified spontaneous emission (ASE) range of the EDF. We also propose the use of a section of un-pumped EDF as a saturable absorber (SA), which suppresses noise spikes caused by the high optical pumping power. Experimental results show that by optimising a length of the SA a single wavelength, high power laser signal can be achieved. In addition, we experimentally demonstrate that the performance of the proposed linear-cavity tunable fibre lasers is better than that of ring-cavity tunable laser counterparts. Specifically, we show that linear-cavity based tunable fibre lasers can achieve higher output power, a larger side mode rejection ratio (SMRR) and narrower laser linewidth than ring-cavity tunable fibre lasers.
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Wen, Yen-chun, and 文彥鈞. "Study of tunable wavelength fiber laser." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/07110453760964345410.
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碩士國立中正大學
物理所
96
The aim of this thesis is to fabricate a tunable wavelength fiber laser based on a figure-eight and ring cavity. The tuning of wavelength was achieved by heating a long-period fiber grating or fiber Brag grating in oven, respectively. It is shown that FBG can offer the most obvious wavelength shifts with temperature changes inside the cavity. The maximum output wavelength shifts were about 2 nm from room temperature to 80 degree. The pulse width obtained with this approach is about 1 ms with the repetition rate of 40 kHz.
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Wu, Chih-Wei, and 吳致維. "Cholesteric Liquid Crystal Based Tunable Fiber Laser." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/atezyf.
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碩士國立中山大學
光電工程學系研究所
102
Laser therapy has a great attraction in past decades because of healing faster, less pain and less swelling. The different wavelength of laser sources is used for different treatment. However, the tuning range of laser wavelength in laser therapy is narrow so far. So, we propose the “cholesteric liquid crystal based tunable fiber laser" device to achieve compact size, low cost and tunable laser. Cholesteric liquid crystal is a 2D periodic strcucture so it is a photonic crystal and there is photonic bandgap in it. When the frequency of incident light locates at the photonic band edges of cholesteric liquid crystal, the velocity of incident light comes to zero. Then, by adding some laser dye into the CLC material and applying external force, there would lase in the mixture of CLC and laser dye. In this thesis, we formulate the CLC fiber laser device and measure the optical property and tunability of laser wavelength. The CLC fiber laser is formulated by CLC (nematic E48 and S811) with adding some laser dye DCM, two pieces of multi-mode fiber and hollow core fiber. However, It’s hard to do a good alignment film at the fiber ends, so the multi-domain of CLC planar texture results in multi-peak lasing output. The multi-mode fiber at incident way uses single-mode fiber to instead. The pumping spot size of SMF is small enough to see the single domain so the output lasing signal would be single mode. Additionally, The temperature controlled tunability of cholesteric liquid crystal fiber laser(SMF in, MMF out) is 22 nm.
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Yang, Xiong. "Continuously tunable narrow-linewidth fiber lasers." Licentiate thesis, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-285556.
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Narrow linewidth tunable fiber lasers have become an important tool in research and in-field applications thanks to their high beam quality, great spectral performance, compact structure and environmental robustness. Many methods have been introduced and developed throughout decades to fulfill the need for rapid wavelength adjustment of these fiber lasers. While maintaining a high-level spectral performance, the ease of manipulation and cost effectiveness of the tuning operation are considered beneficial for the lasers used in real world, and therefore, they are the main focus of the work presented in this thesis. An accurate tuning method with narrow linewidth and compact configuration was achieved in the first work. A polarization independent semiconductor optical amplifier (SOA) was used as the gain medium in a unidirectional fiber ring cavity with a circulator connected to a 6-meter long chirped fiber Bragg grating (CFBG). The laser wavelength was chosen by setting the modulation frequency of the SOA the same as the harmonics of the fundamental repetition rate of the light reflected at a specific point on the CFBG. Careful management of the drive current and pulse width helped to generate laser light of narrow linewidth (less than 0.03 nm) and with low power variation (1.46 dB) over a tuning range of 40 nm. One example of the application of a tunable fiber source was discussed in the second work. An efficient Erbium Ytterbium fiber amplifier, which is seeded by a distributed feedback laser, was designed for continuous-wave differential absorption light detection and ranging (CW DIAL) of atmospheric CO2-concentration. It had a linewidth of 3 MHz, a tuning range of 2 nm over the CO2 absorption peaks at 1.572 μm and an output power of 1.3 W. Wavelength tuning is achieved by adjusting the drive current to the seed laser. Results from the initial CW DIAL testing demonstrate that this tunable fiber source meets the high demands for range resolved atmospheric CO2 monitoring. To conclude, two narrow linewidth tunable fiber lasers have been demonstrated based on different tuning mechanism. The rapid and accurate tuning operation with low output power variation is achieved in both works. The great spectral properties of these fiber sources make them powerful tools to be used in applications such as optical communication, remote sensing, spectroscopy, optical coherence tomography, and many more.Smalbandiga avstämbara fiberlasrar har blivit viktiga instrument inom forskning och andra tillämpningar på grund av deras höga strålkvalitet, goda spektrala egenskaper, kompakthet och stora miljötålighet. Under de senaste decennierna har flera metoder introducerats och utvecklats för att kunna göra snabba våglängdsjusteringar för sådana lasrar, med bibehållande av gott spektralt uppförande. Billiga, smalbandiga, enkelt avstämbara lasrar är viktiga för praktiska tillämpningar, och arbetet i denna avhandling har handlat om att utveckla nya sådana och studera deras egenskaper. I det första arbetet togs en precis avstämningsmetod med smal linjebredd tillsammans med en kompakt utformning fram. En polarisationsoberoende optisk förstärkare av halvledartyp (SOA) användes som fotonkälla i en fiberring-kavitet med en fiberoptisk cirkulatorn kopplad till ett 6 meter långt fiber- Braggitter, ett s.k. ¨chirpat¨, eller kvittrat fiber- Braggitter,( CFBG). Laservåglängden valdes genom att sätta modulationsfrekvensen för SOA-förstärkaren till önskad resonansfrekvens i kaviteten. Endast ljus som reflekterades i en bestämd punkt i CFGBgittret förstärks då, vilket svarade mot den önskade våglängden. Med noggrann inställning av drivström fick man då en smal pulsbredd (mindre än 0,03 nm), avstämbart över ett intervall på 40 nm och med bara en liten variation i effekten (1,46 dB). I det andra arbetet utvecklades en annan avstämbar fiberbaserad laserkälla för att användas i en ny gasmätningsmetod av atmosfären. Metoden utnyttjar kontinuerligt ljus och differentiell absorptions-LIDAR (CW DIAL), där man mäter återspritt ljus från den önskade molekylen på, eller vid sidan om en absorptionslinje hos gasen. Från resultaten kan man sen räkna ut den lokala koncentrationen av gasen med hög spatiell noggrannhet. Lasersystemet bestod av en Yb-Er-fiberförstärkare matad från en smalbandig, avstämbar diodlaser (DFBlaser). Systemet hade en linjebredd på 3 MHz, en avstämbarhet på 2 nm avpassat för absorptionstopparna för CO! vid 1,572 µm, och en uteffekt på 1,3 W. Våglängden kunde ändras genom justering av drivströmmen till DFB-lasern. Systemet användes för att mäta CO! med den nya tekniken för första gången och resultaten visade att den avstämbara fiberkällan motsvarar de höga krav som ställs på monitorering av CO! i atmosfären. Sammanfattningsvis har två avstämbara fiberlasrar med smal linjebredd, baserade på olika avstämningsmekanismer, demonstrerats. För båda lasrarna kan en snabb och noggrann avstämning uppnås, med liten variation i uteffekt. Dessa fiberkällors goda spektrala egenskaper gör dem till kraftfulla verktyg för användning i olika tillämpningar som t.ex. optisk kommunikation, fjärranalys, spektroskopi och optisk koherenstomografi (OCT).
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Jhang, Ya Ru, and 張雅茹. "Study of Tunable Fiber Ring Laser and Mode-locked Laser." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/59504515238012268955.
Full textAbstract:
碩士長庚大學
電機工程學系
101
Recently fiber lasers become more and more sophisticated and applicable for many medical instruments. Until the optical coherence tomography (OCT) spring up, non-invasive techniques become the focus of medical application. People can know whether the cells produce disease under no wound. This technique needs a broadband light source or a sweep source, and it also needs an excellent stability. Therefore, how to design a broadband tunable laser source is one of hot research topics. In this study, a widely tunable ytterbium-doped fiber (YDF) laser using bidirectional pumping scheme at 1060 nm is proposed and demonstrated. This scheme can achieve a higher gain and wider wavelength tuning range compared with traditional structures. With 1.4 m-long commercial YDF as the gain medium, the proposed fiber laser can provide output power of approximately – 5.15 dBm with over 75 nm tuning range under 400 mW pumping power. Moreover, the laser can keep output stable over long-period time of 8 hours and an optical side-mode suppression ratio of higher than 53dB in all the tuning range. In order to achieve the better results for medical imaging detection and medical message transmission, we also improve the scheme to obtain more widely and stable source.
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Hsu, Jing, and 許宜靜. "The Study of Waveband-Tunable Multiwavelength Fiber Laser." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/14395606989966864574.
Full textAbstract:
碩士高雄師範大學
光電與通訊工程學系
98
In recent years, because optical communication industry grows fast, it promotes the development of the wavelength of 1300nm to 1600nm laser light source. The fiber laser structure is simple and connected with optical communication network compatibly due to the small insertion loss. Most importantly the fiber laser satisfies super broadband demand; its development is quite considerable. The waveband-tunable multiwavelength fiber laser is demonstrated in the erbium doped fiber amplifier and semiconductor optical amplifier with the in-line Sagnac interferometer and the interleaver. The schemes are introduced the method of nonlinear polarization rotation effect and hybrid gain medium to suppress the mode competition of homogeneous gain broadening of erbium-doped fiber laser(EDFL), and the laser has good lasing stability. Up to now, many academics have proposed nonlinear polarization effect improving mode competition of EDFL. Our systems are waveband tunable fiber laser and have never studied so far. We hope our structures can offer the reference to the future research. In the experiment, we observe the laser characteristic variation of laser linewidth, faltness, SNR, bandwidth and stability by changing the length of resonance cavity, the ratio of coupler and pump power. We compare our experimental result with former literature and expect to know the advantage and drawback of our system. We hope our system may make improvement in the further.
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Yang, Tzu-Te, and 楊子德. "The study of laser-diode-pumped tunable Ti:sapphire crystal fiber laser." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/8c2g8s.
Full textAbstract:
碩士國立臺灣大學
光電工程學研究所
105
Ti:sapphire crystal is a widely used material. It has a wide emission spectra with center wavelength located around 780 nm and a 180-nm, 3-dB bandwidth. Due to its broadband emission spectra, there are various applications in wavelength tunable lasers and mode-locked lasers. Since its emission wavelength also sits in the region where there is low tissue absorption, there are also applications in biological imaging technologies, such as optical coherence tomography (OCT). To solve the two drawbacks of Ti:sapphire crystal: low absorption cross section and low fluorescence lifetime, Ti3+:Al2O3 single-cladding crystal fiber was grown using the LHPG method. As the laser gain material, crystal fiber with length of 24 mm was used. The single crystal core diameter was 16 μm and the glass cladding outer diameter was 320 μm. The Ti3+ doped concentration was 0.049 wt.%, with regarding to a 0.075 dB/cm attenuation coefficient, which is the lowest value recorded for Ti:sapphire waveguide structures. After end face grinding and polishing, the crystal fiber was coating with dielectric coating using thin film E-gun deposition system to form the required optical cavity structure. By using a 520-nm LD as the pumping source, intra-cavity and external-cavity lasers were constructed. Due to a gain guiding effect, the output mode is near fundamental mode. Under intra-cavity setup, with a 20% output coupler, the laser efficiency and laser threshold were 24.9% and 140.5 mW, respectively. The maximum output power at 1W pumping was 215 mW, achieving high slope efficiency and low threshold simultaneously. Under external-cavity setup, with high reflectance output coupler, the laser efficiency and laser threshold were 18.6% and 123.2 mW, respectively. With wavelength tuning elements, such as inserting a birefringent filter or using a grating output coupler, tunable laser was achieved. Under birefringent filter setup, the tuning was not continuous. The wavelength tuning range was 710-860 nm, with a 150-nm width. Range of output power exceeding 50 mW was 130 nm, providing sufficient output power for various applications. Under grating setup, continuous wavelength tuning was achieved. Continuous range was 693.4- 876.5 nm, with a 183.1 nm width. With 3-dB tuning bandwidth of 143 nm, the broadband emission properties of Ti:sapphire crystal fiber were demonstrated .
25
Song, Po-Shan, and 宋柏賢. "Study of Continuously Wavelength-Tunable Erbium-Doped Fiber Laser." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/26124755199157487175.
Full text
26
Chang, Jun-Yuan, and 張峻源. "Novel Wavelength-Tunable L-band Mode-Locked Fiber Laser." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/80426740839079925381.
Full textAbstract:
碩士國立交通大學
光電工程系所
94
In this thesis, we study the L-band erbium-doped fiber amplifier (EDFA) and wavelength-tunable erbium-doped fiber laser (EDFL), and further accomplish mode-locked EDFL. An extremely high power conversion efficiency (PCE) of 37% (10% improvement as compared to that reported using conventional L-band EDFA configuration) in the optimized configuration of EDFA is obtained. In wavelength-tunable EDFL, the wavelength shifting phenomenon results from the different intracavity loss by adjusting the output coupling ratio with a tunable-ratio optical coupler (TROC). In the tuning range, covering the whole L-band, the EDFL has extremely high output power and quantum efficiency. Besides, the lasing linewidth of the EDFL output becomes narrower by simply inserting an tiny air-gap between the FC/PC connectors of fiber patch cord, which functions as a intra-cavity Fabry-Perot filter in the cost-effective L-band EDFL system. Then the wavelength tuning of mode-locked EDFL is achieved by adjusting the output coupling ratio with a TROC which introduces wavelength-dependent cavity loss as well as changing the peak of the gain profile. And we also add tunable band-pass filter in the cavity to attain wavelength-tuning. Finally, according to the dispersion compensation theory, we use single mode fiber with negative group velocity dispersion (GVD) to compress the mode-locked EDFL output with positively chirped pulse.
27
Hsu, Wei-chen, and 許偉貞. "Nearly Single-Longitudinal-Mode Linear-Cavity Tunable Fiber Laser." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/31158210760549662764.
Full textAbstract:
碩士國立臺灣科技大學
光電工程研究所
100
The thesis investigates nearly single-longitudinal-mode (SLM), linear cavity and wavelength-tunable fiber lasers. Two fiber lasers based on different cavity-end schemes are presented. There are optical circulator (OC) integrated fiber Bragg grating (FBG) type and Faraday rotator mirror (FRM) integrated FBG type. First, we reviewed the theorem of the linear cavity fiber lasers and mentioned prior works done by other group and our lab. Second, we described the SLM design and then we added either sub-ring cavity (SRC) and/or absorber as mode-suppressed element into the fiber laser cavity. In this experiment, we chose 3 m EDFs as the gain medium with OC or FRM to obtain an optical signal-to-noise ratio of more than 55 dB, the largest optical power variation was ±0.9 dB, and the laser span range was 14 nm using tunable FBG. Note that the port 3 was loopback to port 1 of the OC so as unidirectional transmission in the fiber loop may help to partially reduce the mutual injection effect. While the FRM made incident light and reflected light be orthogonal to each other to reduce interference. Furthermore, nearly SLM fiber laser can be achieved by using three SRCs with lengths of 0.75,1 and 1.15 m, respectively, inside the main cavity. On the other hand, used 0.7 m EDF of low absorption coefficient and two SRCs into FRM based fiber laser, nearly SLM operation fiber laser could be obtained. Due to the large insertion losses of the optical components, the OSNR was degraded to 40 dB. The stable SLM wavelength-tunable laser would find vast applications in both optical sensing and optical communications.
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Hsu, Yu-Wei, and 許祐維. "The study of Cr4+:YAG crystal fiber tunable laser." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/mc77g8.
Full textAbstract:
碩士國立臺灣大學
光電工程學研究所
107
Cr4+:YAG crystal is a material for broadband light source. The central wavelength is around 1.4 μm and its 3dB gain spectrum can reach 250 nm. The emission spectrum covered the E, S, C band of optical communication, eyes safe wavelength range and water absorption window. It’s also a ideal candidate for Fourier domain OCT light source since the axial resolution depends on the bandwidth, the widely wavelength tuning range can supply better axial resolution for OCT image. In this thesis, we use laser-heated pedestal growth (LHPG) to growth Cr4+:YAG crystal fiber, and then cladded with glass using co-drawing LHPG process to make double cladding crystal fiber (DCF). The Cr4+:YAG crystal fiber is used as the laser gain media, the wavelength tuning bandwidth is 95 nm, tuning range from 1384.8 nm to 1479.4 nm by using reflective grating as wavelength selector. The both endface of crystal fiber are coated with high quality dielectric coating. The collimated external cavity Cr4+:YAG fiber laser can reach 200 mW output under 3 W pumping. The 12.9% laser efficiency and 51.6 mW low threshold are reach by hemispherical external cavity Cr4+:YAG fiber laser cavity structure. To increase the gross gain in the cavity, a higher Cr4+ ion concentration crystal fiber was made by reducing the heated step of LHPG process. The higher ASE power and less residual pump power implies that more Cr4+ ion remain in crystal fiber than the DCF under usual LHPG process. The measurement result also shows that the concentration of Cr4+ ion remain 40% more in crystal fiber through this process. The gain simulation also shows that if the Cr4+ ion in crystal fiber can recover to original concentration, the gross gain in cavity can reach over 25 dB under double pumping system.
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Wang, Jun-Bo, and 王俊博. "Tunable Photonic Microwave Filter Using Multi-wavelength Fiber Ring Laser." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/89qf6p.
Full textAbstract:
碩士國立臺北科技大學
光電工程系研究所
99
In this dissertation, we study a tunable photonic microwave filter using multi-wavelength fiber ring laser. We propose a tunable multi-wavelength fiber ring laser using Fabry-Perot Laser Diode. By adjusting the optical tunable filter within the ring cavity, the multi-wavelength output can be flexibly tuned; The theoretical analysis and experimental implementation using multi-wavelength fiber ring laser of a tunable photonic microwave filter are presented. The 3-dB bandwidth can be varied through adjustment of the number of output wavelength from tunable multi-wavelength fiber laser. The filter performances are discussed.
30
Chen, Yu-Fan, and 陳宇凡. "Tunable Multi-wavelength Fiber Ring Laser With Ultra-Narrow Spacing." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/w9etfw.
Full textAbstract:
碩士國立臺北科技大學
光電工程系研究所
100
In this dissertation, we experimentally demonstrate a multiwavelength Brillouin-Erbiumto fiber laser by using a high power Brillouin Pump and make it inject into a Single Mode Fiber for generating Stimulated Brilouin Scattering (SBS). The output range and numbers of multi-wavelength fiber ring laser can be flexibly tuned by directly adjusting the output wavelength and power of Brillouin Pump respectively. And measure the power fluctuation during 25 minutes to ensure a stable multi-wavelength light source. Finally, we compare this structure with another multi-wavelength light source using a comb filter and discussed.
31
Huang, Tzu Wei, and 黃子維. "Study of Wavelength Tunable Ytterbium-Doped Fiber Ring Laser Techniques." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/45849307794686181401.
Full textAbstract:
碩士長庚大學
電機工程學系
100
The main purpose in this paper is using ytterbium-doped Fiber Amplifier (YDFA) as a main structure and combining different kinds of optical components to produce ring fiber lasers. These components include Fabry-Perot Filter (F-P filter), Semiconductor Optical Amplifier (SOA) and Polarization Controller (PC) etc. Using different coupling ratios of optical coupler enter into the proposed ring laser structure to get better transfer efficiency, single mode, narrow bandwidth and tunable high power. The optical system simulation software is used to simulate the various performances of YDFA. Then we use the numerical method to analyze different coupling ratios and put simulation results as an experimental basis. Moreover, the three different architectures of experimental setup are shown to improve performances of the tunable ytterbium-doped fiber laser. The experimental data from the observation of different optical components achieve an optimum operating point for the proposed tunable fiber laser. According to the experimental results, the available tunable bandwidth of the laser is up to 55 nm, the output power of 7dBm and power vibration of 1-2dBm in tunable range.
32
陳弘文. "Mode-locked erbium-doped fiber laser with tunable intracavity spectral modulation." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/38909686628891223657.
Full textAbstract:
碩士國立清華大學
光電工程研究所
101
Mode-locked fiber lasers have been extensively explored in recent years because of a variety of practical advantages. The new mode-locking mechanisms of self-similar and all normal dispersion fiber lasers increase the output pulse energy by more than one order of magnitude for the passively mode-locked femtosecond fiber lasers. In this thesis, we demonstrate an erbium-doped fiber oscillator with predominant normal group delay cavity dispersion (GDD) at 1.55 wavelength. A Fourier transform pulse shaper built into the cavity enables the central wavelength and bandwidth of the fiber oscillator to be widely tunable. An extra GDD introduced by the shaper effectively increases the pulse energy and reduces the nonlinear chirp of the output mode-locked pulse. The wave-breaking-free output pulse energy can be increased from 4.3 nJ to 8.9 nJ by adding an extra GDD of 0.178 ps2, limited by the available pump power of 320 mW. The pulse width and stability of the pulse train were thoroughly characterized by intensity autocorrelation, frequency-resolved optical gating, oscilloscope trace, and radio-frequency spectral analysis. Besides, supercontinuum generation from 1200 nm to 2400 nm was generated by a 15-m-long highly nonlinear fiber.
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"Electrical wavelength-tunable pulses generated from semiconductor lasers and erbium doped fiber lasers." 1999. http://library.cuhk.edu.hk/record=b5889909.
Full textAbstract:
by Kit Chan.Thesis (M.Phil.)--Chinese University of Hong Kong, 1999.
Includes bibliographical references.
Abstracts in English and Chinese.
Abstract --- p.ii
Acknowledgment --- p.v
Table of Contents --- p.vi
Chapter 1. --- Introduction --- p.1
Chapter 1.1 --- Ultrashort Pulses Generation in Semiconductor Lasers and Fiber Lasers --- p.2
Chapter 1.2 --- Wavelength Tunable Pulse Generation From Semiconductor Laser --- p.4
Chapter 1.3 --- Wavelength Tunable Pulse Generation from Erbium Doped Fiber Lasers --- p.7
Chapter 1.4 --- Structure of the thesis --- p.8
Reference --- p.10
Chapter 2. --- Principles and Theories --- p.14
Chapter 2.1 --- Principle of Synchronous Injection Seeding --- p.15
Chapter 2.2 --- Principle of Compensated Dispersive Tuning in Self-seeding Configuration --- p.18
Chapter 2.3 --- Principle of Compensated Dispersive Tuning in Actively Mode-Locked Fiber Laser --- p.20
Chapter 2.4 --- Principle of Wavelength Switching in Actively Mode-Locked Fiber Laser with Fiber Bragg Gratings in Cascaded Configuration --- p.24
Chapter 3. --- Electrical Wavelength Tunable Pulses Generated From Two-way Synchronous Injection Seeded Fabry-Perot Laser Diodes --- p.26
Chapter 3.1 --- Introduction --- p.27
Chapter 3.2 --- Experimental Details --- p.28
Chapter 3.3 --- Results and Discussion --- p.31
Chapter 3.4 --- Summary --- p.38
Reference --- p.39
Chapter 4. --- Compensated Dispersive Tuning In Self-Seeding Configuration --- p.41
Chapter 4.1 --- Introduction --- p.42
Chapter 4.2 --- Experimental Details --- p.43
Chapter 4.3 --- Results and Discussion --- p.46
Chapter 4.4 --- Summary --- p.55
Reference --- p.56
Chapter 5. --- Compensated Dispersive Tuning in Actively Mode-Locked Fiber Laser --- p.57
Chapter 5.1 --- Introduction --- p.58
Chapter 5.2 --- Experimental Details --- p.59
Chapter 5.3 --- Results and Discussion --- p.61
Chapter 5.4 --- Summary --- p.69
Reference --- p.70
Chapter 6. --- Compensated Dispersive Tuning in Actively Mode-Locked Fiber Laser Using Linearly Chirped Fiber Bragg Grating --- p.71
Chapter 6.1 --- Introduction --- p.72
Chapter 6.2 --- Experimental Details --- p.73
Chapter 6.3 --- Results and Discussion --- p.75
Chapter 6.4 --- Summary --- p.77
Reference --- p.78
Chapter 7. --- Electrically Wavelength Switching in Actively Mode- locked Fiber Laser Using Fiber Bragg Gratingsin Cascaded Configuration --- p.79
Chapter 7.1 --- Introduction --- p.80
Chapter 7.2 --- Experimental Details --- p.81
Chapter 7.3 --- Results and Discussion --- p.83
Chapter 7.4 --- Summary --- p.87
Reference --- p.88
Chapter 8. --- Conclusion and Future Works --- p.89
Chapter 8.1 --- Conclusion --- p.89
Chapter 8.2 --- Possible Future Works --- p.92
Appendices --- p.A-l
Chapter Appendix A. --- List of Publications --- p.A-l
Chapter Appendix B. --- List of Figures --- p.A-2
34
Winz, Michele W. "The construction and computational modeling of a fiber Bragg grating tunable laser diode." Thesis, 2003. http://hdl.handle.net/1957/30798.
Full textAbstract:
The widespread adoption of wavelength division multiplexing to increase the
bandwidth of optical fiber communication systems has provided a major impetus for
research on low cost, single-mode, wavelength stable tunable diode lasers for use in
optical telecommunications due to the large volume of lasers required. Other
applications, such as demodulation of fiber Bragg grating sensor systems can also
make use of inexpensive tunable laser diodes. In addition, the steady increase in the
amount of computational power available has led to the widespread use of computers
to model physical systems both to predict system performance and to gain insight into
physical behavior.
Following a brief review of the application and construction of optical fiber
Bragg gratings and a discussion of diode lasers and common methods of tuning diode
laser wavelengths, a coupled-cavity approach to modeling laser diode output spectra,
the construction of a fiber Bragg grating wavelength tunable laser, and the coupled
cavity model of the fiber Bragg grating wavelength tunable diode laser are detailed.
The physical laser system consists of a commercial Fabry-Perot diode laser with a
cavity length of 300 microns, antireflection coated with a single layer of SiO, and
coupled into an optical fiber containing a fiber Bragg grating. Wavelength tuning is
accomplished by applying axial strain to the fiber grating. The coupled cavity model
directly includes the antireflection coating, includes the fiber Bragg grating as an
index step, and is the first reported implementation of this method to model fiber
Bragg grating coupled laser diodes. The measured output spectra of the physical laser
diode system and the calculated output spectra are given and compared. Continuous
tuning of the diode laser by applying axial strain to the fiber grating is not observed
nor calculated to occur for a single-layer silicon monoxide antireflection coating. To
achieve continuous wavelength tuning, better antireflection coatings will need to be
developed.Graduation date: 2004
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Lin, Zih-rong, and 林姿蓉. "The Application of Multi-Wavelength Tunable Fiber Ring Laser and Injection-Locked Fabry-Pérot Laser Diode to Optical Fiber Networks." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/40191040321688116490.
Full textAbstract:
博士國立臺灣科技大學
電子工程系
98
In this dissertation, the realization is presented of single-/dual-/multi-wavelength tunable fiber ring laser, which can be applied to performance testing of systems with injection-locked Fabry-Pérot laser diode (FP-LD) and television broadcasting using a low-cost passive optical network (PON). Firstly, we present the realization of tunable single-wavelength fiber ring laser and tunable directly modulated fiber ring laser. For tunable single-wavelength fiber ring laser, a tunable semiconductor optical amplifier-erbium-doped fiber (SOA-EDF) ring laser is presented, using an SOA to suppress cavity mode partition noise at low frequencies. The tunable SOA-EDF fiber ring laser has a tunable wavelength range covering both C- and L-band (1540~1604 nm). The average output power is 2.2 dBm, and optical signal-to-noise ratio (SNR) is above 46 dB. An application is shown for a 10-Gb/s single directional transmission over 50-km single mode fiber (SMF) with a power penalty of 0.94 dB. For tunable directly modulated fiber ring laser having a 2-kHz linewidth, wavelength tuning range is 45-nm (1535~1580 nm) covering both C- and L- band, optical SNR is above 38 dB, and an demonstration is shown for directly modulated 1.25-Gb/s downstream and upstream transmissions, using injection-locked FP-LD. Power penalties less than 0.11 dB and 0.86 dB are demonstrated for the simultaneously transmission over 25-km SMF. Then, we present the application of FP-LD injection-locked by tunable fiber ring laser technique to system performance testing. Moreover, a relatively-low-cost PON system is proposed for television broadcasting and high-speed bidirectional communications. Finally, the realization of dual-/multi-wavelength fiber ring lasers is presented. A tunable dual-wavelength fiber ring laser is shown using an SOA-EDF ring laser framework and two optical tunable filters. The wavelength tuning range is 58-nm (1547~1605 nm) covering both C- and L-band, and the power equalization of the dual-wavelength outputs are less than 1.5 dB. An application is shown for a 10-Gb/s single directional transmission over 25-km SMF with a power penalty of 0.5 dB. Furthermore, a multi-wavelength fiber ring laser is demonstrated using an SOA-EDF ring laser framework and a pair of multiplexer/demultiplexer (MUX/DMUX) with a channel spacing of 0.8 nm (100 GHz) conforming to the International Telecommunication Union (ITU) grid. The lasers can generate four wavelengths simultaneously and side-mode suppression ratio (SMSR) is above 35 dB. The maximum power equalization is less than 0.4 dB and minimum average output power is above -3.3 dBm. Our experimental results show that the sensitivity is -27.94 dBm and the power penalty is 0.88 dB for the transmission of 2.5-Gb/s data over 25-km SMF.
36
Fu, Huan-Chun, and 傅煥鈞. "The research and production of tunable erbium-doped fiber Bragg graing laser." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/89414291994840899941.
Full textAbstract:
碩士長庚大學
電機工程研究所
89
The main body of this paper was with regard to the combination of two kinds of tunable erbium-doped fiber grating lasers by the 980nm laser diode light and the two kinds of optical cavities which were formed at the two sides of erbium-doped fiber separately by Gaussian-apodized and superstructure fiber grating. To focus on the uniform and superstructure fiber gratings, we used computer to simulate their reflection spectrums and regard the peak-wavelengths of these two reflection spectrums as two lasers' output wavelengths which separately have the optical cavity formed by Gaussian-apodized and superstructure fiber grating. Besides, focusing on the two lasers' output wavelengths, we also simulated the relative strain sensitivity of these two wavelengths and they were separately 1.2 and 0.8 . In facts, the apodized fiber grating laser have output wavelength was 1537.80, the linewidth was 0.1nm, the power was about 0.1mW, the wavelength tunable range according to strain was 0.9nm and the relative wavelength-strain sensitivity was 0.715 . As for the produced superstructure fiber grating laser, its optical cavity was formed by the superstructure fiber grating which has two peak-reflecting-wavelengths at the two sides of erbium-doped fiber. This laser can produce two beams of laser which have different wavelengths at the same time and the wavelengths were 1550.840nm and 1552.360nm, the linewidthes were both 0.06nm, and the total power was about 0.63mW.
37
Syu, Yi-Syun, and 許藝薰. "The Study of Tunable Channel Spacing and Power Equalized Multi-Wavelength Fiber Laser." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/35004491806580594566.
Full textAbstract:
碩士國立東華大學
電機工程學系
99
Due to the high speed rate of the WDM transmission system, we would like to construct a multi-channel laser as the signal light source. We develop a multi-wavelength fiber laser which could be tuned channel spacing and equalized laser power to offer a flexible design. Our configuration is composed of a 2´4 and 1´2 coupler, four FBGs, VOAs and EDFs, a pumping of 1480 nm and circulator. Four linear cavities based on 2´4 coupler would avoid mode suppression intelligently. Each mode oscillates in different EDF and VOA controls each mode power easily. The 1´2 coupler extracts each channel from the output port. Thus the multi-wavelength laser operates as single-wavelength laser. Other multi-wavelength fiber laser configurations that based on single gain meadium are present notably suppression and the best performance with suppression of 6 dB. Otherwise we strain FBG to change the channel. To conform the ITU standard, we shift Channel 2 and Channel 3 for every 0.4 nm. The shifting doesn’t affect the channel power remarkably. After the shifting, each channel power could be maintained on the level of 5.7 dBm by tune the VOA and the power difference below to 0.5 dB within all the channels. This performance depends on the single-channel-like operation. Therefore we complete a tunable channel spacing and power equalized multi-wavelength fiber laser. This is a flexible light source when it is applied on WDM system.
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Chen, Shih Hsuan, and 陳仕軒. "Study of Hybrid Bidirectional Pumping Technique to Tunable Ytterbium-Doped Fiber Ring Laser." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/mdeyb8.
Full text
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"New methods to generate wavelength-tunable pulses from semiconductor and fiber lasers using the dispersion tuning approach." 2000. http://library.cuhk.edu.hk/record=b5890335.
Full textAbstract:
Lee Ka-lun.Thesis (M.Phil.)--Chinese University of Hong Kong, 2000.
Includes bibliographical references.
Abstracts in English and Chinese.
Abstract --- p.ii
Acknowledgment --- p.v
Table of contents --- p.vi
List of figure --- p.viii
Chapter 1. --- Introduction --- p.1
Chapter 1.1. --- Generation of picosecond pulses from semiconductor laser and fiber laser --- p.2
Chapter 1.2. --- Wavelength tunable pulse generated from semiconductor laser --- p.5
Chapter 1.3. --- Wavelength tunable pulse generated from erbium doped fiber laser --- p.7
Chapter 1.4. --- Structure of the thesis --- p.8
Chapter 2. --- Principles and Theories --- p.13
Chapter 2.1. --- Principle of dispersion tuning --- p.15
Chapter 2.1.1. --- Dependence on the strength of dispersion --- p.16
Chapter 2.1.2. --- Wavelength selection in time domain --- p.18
Chapter 2.1.3. --- Compensated dispersion tuning in a dispersion balanced fiber ring --- p.20
Chapter 2.2. --- Optical gating using Nonlinear Optical Loop Mirror (NOLM) incorporated with nonlinear element --- p.22
Chapter 2.3. --- Principle of compensated dispersion tuning in harmonically mode- locked fiber laser incorporated with linearly chirped fiber grating (LCFG) --- p.26
Chapter 2.4. --- Principle of compensated dispersion tuning in self-seeding configuration --- p.29
Chapter 2.5. --- Principle of dual-wavelength operation in harmonically mode-locked fiber laser --- p.31
Chapter 3. --- Preliminarily experimental study --- p.33
Chapter 3.1. --- Wavelength selection using strong and weak dispersive medium --- p.34
Chapter 3.2. --- NOLM as a fast optical modulator --- p.38
Chapter 4. --- Self-compensated dispersion-tuning in mode-locked fiber laser using bi- directional transit in a linearly chirped fiber grating --- p.41
Chapter 4.1. --- Introduction --- p.42
Chapter 4.2. --- Experimental Details --- p.43
Chapter 4.3. --- Results and discussion --- p.47
Chapter 4.4. --- Summary --- p.54
Chapter 5. --- Generation of wavelength tunable pulses from a self-seeded semiconductor laser using an optically controlled Nonlinear Optical Loop Modulator (NOLM) incorporated with a Semiconductor Optical Amplifier (SOA) --- p.56
Chapter 5.1. --- Introduction --- p.57
Chapter 5.2. --- Experimental Details --- p.58
Chapter 5.3. --- Results and discussion --- p.64
Chapter 5.4. --- Summary --- p.71
Chapter 6. --- Alternate and Simultaneous Generation of 1 GHz Dual-Wavelength Pulses from an Electrically-Tunable Harmonically Mode-locked Fiber Laser --- p.74
Chapter 6.1. --- Introduction --- p.75
Chapter 6.2. --- Experimental Details --- p.76
Chapter 6.3. --- Results and discussion --- p.80
Chapter 6.4. --- Summary --- p.87
Chapter 7. --- Conclusion and Future works --- p.89
Chapter 7.1. --- Conclusion --- p.89
Chapter 7.2. --- Future works --- p.93
Appendix --- p.A-l
List of Publication --- p.A-l
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Lai, Chang-Liang, and 賴長良. "The Optimum Investigation of L-band Tunable Linear-Cavity Erbium-Doped Fiber Laser (EDFL)." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/18536299803678922435.
Full textAbstract:
碩士國立臺灣科技大學
電子工程系
96
The thesis investigates the optimization of linear-cavity erbium-doped fiber laser (EDFL) both in simulation and experiment. The thesis also discusses several parameters which usually not be released by Fiber developed companies likes Fibercore© and so on. The simulation tool here is Optisystem 6.0 and the saturation parameter we suggested is . Based on the mathematical formula, the final output power could be obtained and the light intensity along the cavity could be tracked after parameters are setted. Hereafter, experimentally study the EDFL both in forward pumping and backward pumping schemes are investigated. The length of gain fiber, the pump laser, reflectivity of the fiber Bragg grating (FBG) are 6 M, 100 mW and 50%, respectively. We conclude that the backward pump EDFL has better charactersitics in threshold power and lasing output power than those of the forward pump EDFL. Based on the experimental and simulated results, the most suitable length of EDF is suggested to be 5 to 8m, and the optimum reflectivity of FBG is around 21%. Using a FBG with a center wavelength of 1582 nm, as well as 5M EDF and FBG of 20% reflectivity, a slope efficiency of 33% in 4.9mW threshold power and 30mW laser output power are achieved. Using a FBG with a center wavelength of 1596 nm, the values of them will be 25.1%, 6 mW and 23.6 mW, respectivwly. The fixed-wavelength EDFL structure could be extended into a tunable-type EDFL in the same EDF length while the optimum reflectivity of tunable FBG will be changed to around 50% under the consideration of the extending of tunable range of FBG. For example, the allowable wavelength tunable range are 6nm and 13nm when the reflectivities of FBGs are 20% and 50%, respectively.
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Yang, Feng-Yi, and 楊峯宜. "Wavelength-Tunable Erbium-Doped Fiber Ring Laser and Its Application in Acetylene Gas Sensing." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/87638414184381066222.
Full textAbstract:
碩士逢甲大學
光電學系
101
This work studies a wavelength-tunable erbium-doped fiber ring laser based on an all-fiber tunable two-cascaded UMZI (Unbalanced Mach–Zehnder Interferometer, UMZI) filter. This filter is composed of two optical fiber Mach-Zehnder interferometers, and two electronic phase lock loops are used to control their optical path differences for a stable and adjustable loss spectrum. The wavelength tuning range、full width at half maximum、maximum side-mode suppression ratio、slope efficiency、output power stability and wavelength stability of the fiber ring laser are about 4 nm、23 pm、50 dB、1.05%、0.67 dB and 0.05 nm, respectively. The output wavelength range of the fiber ring laser can be further increased by increasing the length of the erbium-doped fiber and adding a tunable bandpass filter in the resonant cavity. By these additions, any output wavelength between 1535 nm and 1565 nm can be selected with a 4-nm tuning range. We have used this fiber ring laser to implement an all-fiber intra-cavity pressure sensor for acetylene sensing, using the evanescent wave spectroscopic absorption of a 1-μm optical fiber taper. If the pump power of the fiber ring laser is set above the lasing threshold, the sensitivity of the acetylene pressure measurement is about 0.0077 dB/mbar.
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TSAI, LI-YEN, and 蔡立言. "Continuously wavelength tunable passive-mode locked Er-doped fiber laser based on graphene oxide." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/5377wr.
Full textAbstract:
碩士國立臺北科技大學
光電工程系
107
Title: Continuously wavelength tunable passive-mode locked Er-doped fiber laser based on graphene oxide School: National Taipei University of Technology Page: 55 Department: Institute of Electro-Optical Engineering Time: June, 2019 Degree: Master Researcher: Li-Yen Tsai Advisor: Ja-Hon Lin Key word: Er-doped fiber laser; graphene oxide; saturable absorber; mode-locking; Tunable wavelength fiber laser; hybrid mode locking In this work, I investigated the wavelength tunable passive mode-locked Er-doped fiber laser in combination with the graphene oxide (GO) and nonlinear polarization rotation (NPR) mechanism. In order to produce the GO/PVA film, the GO suspension in DI water will be produced by the liquid phase exfoliation technique and then centrifuge. The upper-layer GO suspension was mixed with the polyvinyl alcohol (PVA) solution and dried in plastic model to form the GO/PVA composite film. The GO/PVA film shows the high transmittance around 75.16% at 1562 nm. From micro-Raman spectrum, the characteristic peak of GO at D (1347 cm-1) and G (1589 cm-1) band was revealed with intensity ration (ID/IG) around 1.05. From nonlinear transmittance measurement, the GO/PVA film revels modulation depth around 18.4 % at 1564 nm. Unlike mode-locked mechanism based only on the GO/PVA or NPR, the widely and fine tuning wavelength from 1544 nm to 1574 nm has been demonstrated using the hybrid mode-locked mechanism. The EDFL reveals fundamental mode locked state (FML) state in operation at longer wavelength within 1566nm to 1574 nm and fourth-harmonic mode locked (FHML) state in operation at short wavelength between 1544 nm to 1565 nm. Through the theoretical estimation, the tuning mechanism was attributed to the invisible filter using the NPR mechanism. Finally, the long-term stability of PML-EDFL was confirmed by monitoring the output spectrum for three hours. The generated broader wavelength tunable PML-EDFL can meet many potential applications and high commercial value in the future.
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Liu, Feng Chou, and 劉鳳洲. "Wavelength Tunable And Pulsewidth Stretchable Femtosecond Mode-Locked Fiber Laser Based On Dispersion Engineering Technique." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/39512159287043572743.
Full textAbstract:
碩士國立聯合大學
光電工程學系碩士班
100
We demonstrate a pulsewidth tuning and wavelength-tunable femtosecond mode-locked fiber laser by using an intracavity short-pass edge filter. When the filter is thermo-optically tuned to overlap the constituting spectral components of mode-locked pulses, large negative waveguide dispersion is introduced by the steep cutoff slope and the total cavity dispersion is moved to normal dispersion regime to broaden the pulsewidth. Pulse stretch ratio of 3.53 (623.8fs/176.8fs) can be efficiently achieved under a temperature variation of 4ºC or tuned toward shorter wavelengths to strongly attenuate the wavelengths longer than the cutoff, the constituting wavelengths of the mode-locked fiber laser move to shorter wavelengths and the laser center wavelength can be tuned over 1539.7~1560 nm The cavity dispersion get fast switching between the anomalous dispersion regime or normal dispersion to highly efficient pulse stretchable stretching or keep small fluctuations of laser pulsewidth when the laser wavelength is tuned.
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"Optically-controlled generation of wavelength-tunable pulses from semiconductor and fiber lasers using a nonlinear optical loop mirror." 2001. http://library.cuhk.edu.hk/record=b5890622.
Full textAbstract:
Tang Wing-Wa.Thesis (M.Phil.)--Chinese University of Hong Kong, 2001.
Includes bibliographical references.
Abstracts in English and Chinese.
Abstract --- p.i
Acknowledgement --- p.iv
Table of contents --- p.v
List of figure --- p.viii
Chapter 1. --- Introduction --- p.1
Chapter 1.1. --- Introduction to ultrashort optical pulse generation --- p.2
Chapter 1.2. --- Introduction to wavelength-tunable pulse generation --- p.5
Chapter 1.3. --- Introduction to chapters --- p.7
Chapter 2. --- Principles and Theories --- p.11
Chapter 2.1. --- Principle of dispersion tuning --- p.12
Chapter 2.2. --- SOA nonlinear optical loop mirror --- p.16
Chapter 2.3. --- Principle of dispersion tuning in harmonically mode-locked fiber laser using nonlinear optical loop mirror --- p.19
Chapter 2.4. --- Principle of re-configurable multi-wavelength pulses generationin a self-seeded laser diode incorporating SOA loop mirror --- p.22
Chapter 3. --- Rational harmonic mode-locking of an optically triggered fiber laser incorporating a non-linear optical loop modulator --- p.25
Chapter 3.1. --- Introduction --- p.26
Chapter 3.2. --- Experiment --- p.27
Chapter 3.3. --- Result and discussion --- p.30
Chapter 3.4. --- Summary --- p.37
Chapter 4. --- Generation of amplitude-equalized optical pulses from a rational harmonic mode-locked fiber laser incorporating a SOA loop modulator --- p.40
Chapter 4.1. --- Introduction --- p.41
Chapter 4.2. --- Experiment --- p.42
Chapter 4.3. --- Result and discussion --- p.44
Chapter 4.4. --- Summary --- p.47
Chapter 5. --- Optically controlled dispersion-tuning in harmonically mode-locked erbium doped fiber laser using SOA nonlinear loop modulator --- p.49
Chapter 5.1. --- Introduction --- p.50
Chapter 5.2. --- Experiment --- p.51
Chapter 5.3. --- Result and discussion --- p.54
Chapter 5.4. --- Summary --- p.58
Chapter 6. --- Alternate method of constructing harmonically mode-locked fiber laser incorporating SOA nonlinear loop modulator --- p.60
Chapter 6.1. --- Introduction --- p.61
Chapter 6.2. --- Experiment --- p.62
Chapter 6.3. --- Result and discussion --- p.65
Chapter 6.4. --- Summary --- p.69
Chapter 7. --- Optically re-configurable multi-wavelength pulse source constructed from a self-seeded laser diode --- p.71
Chapter 7.1. --- Introduction --- p.72
Chapter 7.2. --- Experiment --- p.74
Chapter 7.3. --- Result and discussion --- p.77
Chapter 7.4. --- Summary --- p.82
Chapter 8. --- Tunable alternating multi-wavelength pulse source constructed using non-linear optical control of wavelength switching in a self-seeded laser diode --- p.85
Chapter 8.1. --- Introduction --- p.86
Chapter 8.2. --- Experiment --- p.87
Chapter 8.3. --- Result and discussion --- p.89
Chapter 8.4. --- Summary --- p.92
Chapter 9. --- Conclusion and future works --- p.94
Chapter 9.1. --- Conclusion --- p.94
Chapter 9.2. --- Possible future works --- p.98
Appendix
List of publications --- p.A-1
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XU, WEN-KAI, and 許玟凱. "Study of Wavelength-Tunable Erbium-Doped Fiber Laser with Gain Control and Interferometric Techniques in the Ring Cavity." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/8wj3ez.
Full textAbstract:
碩士國立聯合大學
光電工程學系碩士班
105
In this study, the ring resonator with the gain medium supported by the erbium-doped fiber amplifier was used to construct the prototype of erbium-doped fiber laser. To further understanding the characteristics of the output lasing wavelength, the gain of the ring resonator was controlled to analyze the relation between the gain and lasing wavelength. Firstly, in the condition of varied attenuation of 0, 26.6, and 60.0 dB, the lasing mode with dual mode, three-mode, and four-mode were obtained, respectively. To reduce the signal power in the loop by the variable optical attenuator, the gain of the band of shorter wavelengths are large than the band of longer wavelengths to generate the output lasing wavelengths of C-band. Without attenuation of the loop, the bands of longer wavelengths with larger value of gain will have the lasing wavelengths in the L-band. Secondly, the interfering techniques were used in the ring cavity of the erbium-doped fiber laser to achieve the effect of tunable wavelength. Two kinds of interferometry were used in the experiments, one is the Mach-Zehnder (M-Z) type and the other is the Sagnac type. With the M-Z interferometer in the erbium-doped fiber loop, the polarization controller was used to generate the phase difference of the sensing arm. The lasing wavelength has the filtering effect and the output single wavelength in the L-band is the result of the combinations between the sensing arm and the reference arm. In the following, with the Sagnac interferometer in the loop, the two opposite beams of light were interfered in the same path. In this path of loop, a polarization controller was used to tune a single wavelength output in the C-band. Finally, the M-Z erbium-doped fiber laser with the variable optical attenuator and the adjustment of tilt angle of the interfering plane will generate the additional optical path differences due to the rotational inertia of the two interfering beams. This results in the tunable lasing multi- and single wavelength output in the C-band.
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Leung, Ka-Hei, and 梁家熙. "The Study of tunable spacing multi-channel hybrid Raman/EDF fiber laser with Double Pass Mach Zehnder Interferometer." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/39303046451440942215.
Full textAbstract:
碩士國立東華大學
光電工程研究所
98
In this paper we presented a multi-wavelength fiber laser structure using a MZI (Mach Zehnder Interferometer) to tune the wavelength spacing. The investigation is mainly in the researches of Mach Zehnder Interferometer structure, resonance cavity structure and gain medium. In the design of interference of Mach Zehnder Interferometer, we employed a manual OVDL (Optical Variable Delay Line) to change the phase difference in two optical paths, so the channel spacing of laser would continuously be tuned from 0.2nm to 1.9nm. We not only designed the tunability of Mach Zehnder Interferometer, but also improved the SNR (Single to Noise Ratio) of interference from 9.7dB to 18.8dB in our Double pass Mach Zehnder Interferometer, which led to the SNR of lasing channels can be over 50dB above in the spacing range. In our ring cavity and linear cavity laser experiments, as the ring cavity structure of which the wave was travelling in one direction while the linear cavity structure of which the wave was back and forth to form a standard wave, so the different resonance properties affected the number of lasing channels. For example, the channel spacing 0.2nm of Erbium Doped Fiber Laser which has only 5 channels in the ring cavity structure, whereas the linear cavity structure could generate 9 lasing channels. Therefore, compared between different laser structures, the linear structure multi-wavelength laser could effectively increase the number of channels. Moreover, we employed the different gain mediums with an EDF (Erbium Doped Fiber), a DCF (Dispersion Compensation Fiber) and a hybrid fiber in the laser structure. The hybrid fiber consisted of an erbium doped fiber and a Raman fiber. In the EDF fiber laser which the EDFA consisted of a 5.58m erbium doped fiber. Although the laser has higher gain and higher SNR, it also has serious homogeneous line broadening and strongly mode competition. So it was difficult to reach multi-wavelength and flat output. For example, the laser output only contained 9 lasing channels and ±4.75dB flatness in the spacing 0.2nm. In the Raman gain fiber laser experiment, the number of lasing channels could reach to 33 and ±4.07dB flatness in spacing 0.4nm, which the RFA consisted of a 4.47km dispersion compensation fiber and it belongs to inhomogeneous broadening mechanism. However, it was limited by the pumping power which led to not sufficient Raman gain to support a large portion of channels over the laser threshold, when the channel spacing was 0.2nm. In the Hybrid gain medium, we focused on the suitable pumping wavelength and the pumping power, because we could clearly understand that these would affect the number of lasing channels and the flatness. In the first experiment, the hybrid gain laser which had a few lasing channels and it was even fewer than the Raman laser when it was pumped by 977.3nm and 1465nm. In the end of our experiment, thereby we designed only two pumping wavelengths, which were 977.3nm and 1480nm, to generate more lasing channels and great flatness output effectively. For example, the number of lasing channels could increase up to 60 with operating channel spacing of 0.2nm, the lasing bandwidth was 12.9nm and the flatness was ±4.2dB.
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Lu, Tai-Chaun, and 盧台全. "Study of a Hybrid Mode-locked Er-doped Fiber Laser with Doubled Repetition Rate and Tunable Alternating Pulse Amplitude/Width." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/94rr9w.
Full textAbstract:
碩士國立交通大學
光電工程研究所
107
In a hybrid harmonic mode-locked Er-doped fiber laser by using 10 GHz active phase modulation and passive nonlinear polarization rotation (NPR) effects, we discover a new interesting mode-locking state with a 20 GHz doubled pulse repetition rate and the alternating pulse amplitude/width output. Experimentally we can tune the modulation frequency, modulation depth and polarization controllers to adjust the relative amplitudes between the adjacent two pulses or to tune the laser back to the 10 GHz mode-locking state. Theoretically we have used the master equation model to simulate the overall field evolution behavior during time evolution and estimate the laser output when the steady state is reached. Nice agreement between the theoretical and experimental results is achieved.
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Yamdagni, Sumeet. "Fiber Bragg Grating Interrogation Systems." Thesis, 2009. http://hdl.handle.net/2005/925.
Full textAbstract:
This thesis work deals with the development of three different categories of interrogation techniques for Fiber Bragg Grating based sensor networks. Such networks are used for structural health monitoring and other applications.
A bulk grating based interrogation system is described first, which includes an optical source, switch, circulator, embedded controller, and software. The center wavelength determination technique employed is detailed and is shown to be highly accurate from test data. The comparison with resistance strain gauges is presented which shows that the system developed provides an accurate strain reconstruction. The system is also compared with a commercial optical spectrum analyzer and is found to exhibit good accuracy and fidelity. The system has been field tested on an aircraft structure with 14 sensors spread over 4 channels. Strain data reconstruction from these tests is shown to accurately reproduce the loading conditions.
A second system developed is based on the matched filter technique using a mechanical fiber stretcher; the details of this system are presented with a mathematical treatment of the technique. The design of the fiber stretcher is also described. This design is regarded to be novel since it tries to provide large interrogation bandwidths using a parallel topology. The results of tests have shown good resolution and comparative tests with resistance strain gauges have shown accurate reproduction of strain.
Finally, an interrogation system based on a wavelength tunable source is presented. This system is a precursor to a time division multiplexed interrogation system, which has also been described. Three laser configurations have been set up and characterized. The laser sweep tests have been performed on two configurations and a sensor grating reconstruction test has also been carried out.
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Lu, Shao-Sheng, and 陸劭晟. "Studies of stable and wavelength tunable fiber lasers." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/80571046028788480256.
Full textAbstract:
碩士國立交通大學
光電工程學系
100
In the first part of this thesis, we proposed a stable and wavelength-tunable semiconductor optical amplifier SOA-based fiber laser with Sagnac ring configuration. Here, this fiber ring laser is SOA-based with Sagnac loop mirror to achieve single-frequency output and save energy power. In the second part, we proposed a dual reflected structure erbium-doped fiber (EDF) laser in single-longitudinal-mode (SLM) for wavelength-tuning. The dual reflected structure of EDF laser with a linear cavity employing a passive saturated absorber based (SAB) filter and tunable bandpass filter (TBF) for the SLM lasing and wavelength tuning. In the third part, we proposed a using Saganc loop of optical-injected semiconductor laser scheme for stable and continuous wave (CW) wavelength-tuning. It is by using self-injected Fabry-Perot laser diode (FP-LD) with Saganc loop scheme. And to achieve the continuous wavelength tuning, we can adjust the temperature of FP-LD for wavelength shifting in the laser scheme. In the fourth part, we proposed a stable wavelength-tuning laser in single-frequency by optical-injected FP-LD and reflective semiconductor optical amplifier (RSOA) for long fiber distance propagation. Finally, the output power, wavelength tunable range, side-mode suppression ratio (SMSR) and output stability of the four proposed laser configurations have been experimentally demonstrated and discussed.
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Hsueh, Chih-Chien, and 薛志堅. "Study of C-band and L-band Tunable Fiber Lasers By Bending Single Mode Fiber." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/77011711280446204826.
Full text