Дисертації з теми "Phase-Locked lasers"
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Boyd, Richard L. (Richard Lyman). "An optical phase locked loop for semiconductor lasers." Thesis, Massachusetts Institute of Technology, 1988. http://hdl.handle.net/1721.1/35943.
Повний текст джерелаTitle as it appeared in MIT Graduate list, June, 1988: An optical phase locked loop.
Includes bibliographical references.
by Richard L. Boyd.
M.S.
Avramopoulos, Hercules. "Phase effects in dispersion compensated passively mode-locked lasers." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47342.
Повний текст джерелаStolarz, Piotr Michal. "Development of a phase-sensitive pulse measurement technique for semiconductor mode-locked lasers." Thesis, University of Glasgow, 2012. http://theses.gla.ac.uk/3368/.
Повний текст джерелаOzharar, Sarper. "Stable optical frequency comb generation and applications in arbitrary waveform generation, signal processing and optical data mining." Orlando, Fla. : University of Central Florida, 2008. http://purl.fcla.edu/fcla/etd/CFE0002388.
Повний текст джерелаAuroux, Vincent. "Application des lasers fibrés à verrouillage de modes à la génération très haute fréquence à haute pureté spectrale." Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30103/document.
Повний текст джерелаThe important rise of telecommunication systems in the past decades, together with the sensitivity improvement of radar systems, has increased the necessity for high spectral purity frequency references at high frequencies. The saturation of classical microwave bandwidths motivated the search of frequency references at higher frequencies, such as K-band. Frequency multiplication from highly stable sources, such as quartz sources, is limited by the increase of the noise floor, which is often prohibitive at millimeter wave frequencies. On the contrary, microwave generation using optics becomes a very efficient technique in this frequency range. Indeed, passive optical resonators or delay lines feature a high Q factor which can be used to stabilize the microwave frequency. The best phase noise performance is today obtained with long delay line oscillators. However, a spurious mode suppression technique has to be implemented in this type of OEOs. The use of an active optical resonator is a third solution, which avoids any locking technique between the laser and the passive resonator. The first architecture of this type has been proposed at the end of the 1990's. In such a system, a mode-locked laser is coupled to a microwave oscillator (COEO). COEO phase noise performances are strongly dependent on the spectral purity of the mode locked laser signal. This thesis work focus on the study and the optimization of this system. Optical amplifiers noise is firstly investigated, in order to determine the optimal conditions to minimize their phase noise contribution to the COEO. A 10 GHz SOA based COEO has been realized and features a low phase noise level reaching - 132 dBc/Hz at 10 kHz from the carrier. An analytical model has also been developed to obtain the locking range of the coupled oscillations. This frequency range is strongly dependent on the coupling efficiency between optical oscillation and the optoelectronic oscillation. This parameter cannot be calculated analytically and an iterative model has been proposed to determine the amplitude and phase of the optical spectrum. Therefore, one can calculate the RF power on the photodiode, on which the coupling efficiency is depending. Since COEO features a large optical frequency comb where each tooth of the comb is phase locked thanks to the mode locked laser, harmonic generation from COEO is possible. Wide frequency comb from high frequency COEO allow millimeter wave generation. The iterative model developed in this work enable to determine the RF power of one specified harmonic from experimental parameters. Harmonic selection can also be performed through the management of the chromatic dispersion. Such frequency multiplication has been implemented to generate a high purity 90 GHz signal from a 30 GHz COEO.These results are promising and an integration of the system in a thermalized box is under process
Hoghooghi, Nazanin. "Injection-locked semiconductor lasers for realization of novel RF photonics components." Doctoral diss., University of Central Florida, 2012. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5303.
Повний текст джерелаID: 031001383; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Title from PDF title page (viewed May 22, 2013).; Adviser: Peter J. Delfyett, Jr.; Thesis (Ph.D.)--University of Central Florida, 2012.; Includes bibliographical references (p. 106-110).
Ph.D.
Doctorate
Optics and Photonics
Optics and Photonics
Optics
Sun, Yifan. "Theory of mode-locked lasers based on non-conventional cavity modes." Thesis, université Paris-Saclay, 2021. http://www.theses.fr/2021UPASP003.
Повний текст джерелаThis PhD thesis mainly addresses the dynamics and the robustness of a novel concept of mode locking in ultracompact semiconductor nanolasers. Such a nanolaser exhibits Hermite-Gaussian modes created by a harmonic photonic cavity to confine light. This maps the optical cavity into quantum mechanical harmonic oscillator, with evenly spaced eigenfrequencies, an essential requirement for mode locking. The possible nonlinear regimes are described by the Gross-Pitaevskii equation with a parabolic potential and nonlinear terms describing gain and absorption. To investigate these dynamical behaviors, direct numerical simulations are mainly implemented. Continuation calculations are also performed using pde2path.First, the mode competition for gain among Hermite-Gaussian modes in the absence of saturable absorption is investigated and shown to be very different from usual resonators.Second, mode locking is predicted to occur with instantaneous saturation of gain and absorption over a broad range of parameters, corresponding to the emergence of dissipative soliton and multisoliton solutions. The mode locking period is controlled by the design of the photonic potential, and not by the cavity length. The dissipative soliton is well described by the coherent state of a quantum mechanical oscillator, namely a Gaussian envelope oscillating without deformation.Third, in the regime of noninstantaneous gain and absorption saturation, different dynamical behaviors of the nanolaser are obtained by varying the gain and the absorption. These different regimes, including Q-switching, Q-switched mode locking, and CW mode locking, are described in detail, illustrating the rich physics of this nonlinear system. The influence of the Henry factor on the mode locking is also discussed. Moreover, similar dynamical behaviors using spatially separated gain and absorber sections inside the cavity are obtained.Fourth, the robustness of mode locking of the Hermite-Gaussian modes to the disorder of the harmonic cavity is investigated in details. It includes the effect of non-parabolicity of the potential and the random errors in the shape of the potential
Karuseichyk, Sopfy. "Noise in coupled VECSEL array." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS162.
Повний текст джерелаLaser arrays are key components in many areas of science, technology, and civilian applications today. A remarkably new domain of application of laser arrays is the laser solver, which allows to parallelize the computation process spatially. For such applications a low noise array with identical laser's characteristics is required. At the same time, most of the listed applications require a coupling mechanism for the array. Most commonly, solid-state lasers are used today for such applications.However, in this work we present a new type of laser array based on the VECSEL (Vertical External Cavity Surface Emitting Lasers) with the intracavity coupling control. Such lasers are well known to be extremely low noise lasers. Their dynamics are a remarkable example of class-A dynamical behavior. Such dynamics is accompanied with the filtering of the transferred pump noise above the cavity cut-off frequency. At the same time the VECSEL is a semiconductor laser, which has distinguishing peculiarities, when compared with the solid-state laser. For example, it has a non-negligible Henry factor. Dynamics of such phase locked VECSEL arrays has not been studied yet.This laser is developed with a planar spatially degenerate cavity. Thanks to cavity degeneracy we transform a multimode VECSEL into an array of independent lasers with a designed loss mask. Thanks to the method of array development with a mask, we gain control on the coupling between lasers by the diffraction on the mask. The coupling is determined by the diffraction on the edges of the mask holes and consequent reflection on the output cavity mirror. Reflected field of each laser is injected to the neighboring holes. The coupling coefficient is complex. We numerically quantify it and then develop several models for the laser array dynamics description with considered complexity of the coupling coefficient. Each model characterizes one of the investigated mask topologies.Changes of the mask position were shown experimentally to change the coupling between lasers from zero to values large enough to phase-lock the laser array. We performed a noise measurement both for the unlocked and phase-locked solutions. The measured relative intensity noise spectra of individual lasers confirmed the class-A dynamics of the developed VECSEL array. Based on the cross-correlation on the noises of different lasers we discovered a clear correlation between phase-locking and a noises spectral correlation. Then, we could reproduce numerically and analytically the same results based on the models we developed.A particular interest of the project was situated on a ring laser array. Such arrays are known for their discrete series for the phase-difference solutions when phase-locked. We studied such solutions in our system. Each of them, except for the in-phase phase-locking, corresponds to a vortex with discrete phase increment between lasers. Since good quality vortices are extremely needed for particle micromotoring, information transfer, etc. we deeply studied such solutions in our system. We studied the limitations dictated by the Henry factor and derived a general analytical criterion for the existence of such solutions. We studied asymmetric vortex generation with non-uniform loss masks. Additionally, we studied theoretically the influence of optical feedback on the phase -locking in such a vortex. The noise model of such an array was experimentally confirmed with three lasers. Based on the model we found a simple method of the determination of the vortex sign (direction of the phase accumulation) based on the laser's noise measurements
Kassa, Wosen Eshetu. "Modélisation électrique de laser semi-conducteurs pour les communications à haut débit de données." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1016/document.
Повний текст джерелаThe advancement of digital optical communication in the long-haul and access networks has triggered emerging technologies in the microwave/millimeter-wave domain. These hybrid systems are highly influenced not only by the optical link impairments but also electrical circuit effects. The optical and electrical effects can be well studied at the same time using computer aided tools by developing equivalent circuit models of the whole link components such as semiconductor lasers, modulators, photo detectors and optical fiber. In this thesis, circuit representations of the photonic link components are developed to study different architectures. Since the optical light source is the main limiting factor of the optical link, particular attention is given to including the most important characteristics of single mode semiconductor lasers. The laser equivalent circuit model which represents the envelope of the optical signal is modified to include the laser phase noise properties. This modification is particularly necessary to study systems where the optical phase noise is important. Such systems include optical remote heterodyne systems and optical self-heterodyne systems. Measurement results of the laser characteristics are compared with simulation results in order to validate the equivalent circuit model under different conditions. It is shown that the equivalent circuit model can precisely predict the component behaviors for system level simulations. To demonstrate the capability of the equivalent circuit model of the photonic link to analyze microwave/millimeter-wave systems, the new circuit model of the laser along with the behavioral models of other components are used to characterize different radio-over-fiber (RoF) links such as intensity modulation – direct detection (IM-DD) and optical heterodyne RoF systems. Wireless signal with specifications complying with IEEE 802.15.3c standard for the millimeter-wave frequency band is transmitted over the RoF links. The system performance is analyzed based on EVM evaluation. The analysis shows that effective analysis of microwave/millimeter-wave photonics systems is achieved by using circuit models which allows us to take into account both electrical and optical behaviors at the same time
Akrout, Akram. "Contribution à l’étude des lasers à verrouillage de modes pour les applications en télécommunications." Thesis, Evry, Institut national des télécommunications, 2009. http://www.theses.fr/2009TELE0023/document.
Повний текст джерелаThis PhD thesis deals with the integration of InP based quantum dash mode locked lasers for use in optical communication systems and microwave optoelectronic applications. The properties of pulse and characterization methods are described as well as requirements for application in communication systems. Experimental and analytic method for pulse “chirp” characterization and compensation are also discussed. In particular, we demonstrate that high order dispersion can be compensated using specific fibre length. The characterization of quantum dash based mode locked lasers, has shown their potential to generate high spectral purity self-pulsating signals, with state-of-the-art spectral linewidth of ~ 850 Hz. Especially, the importance of, and way to reduce high-frequency jitter is discussed. Indeed, a novel method for measurement of high-frequency jitter based on optical cross-correlation technique is implemented. Systematic investigation of 10 GHz passively mode locked laser based on InAs/InP quantum dashes emitting at 1.55 µm have demonstrated a reduced value of timing jitter of 500 fs in the 150 kHz – 320 MHz frequency range. Compared to typical passively mode-locked quantum well laser which exhibit timing jitter in the range 12 ps (150 kHz – 50 MHz), our device demonstrates an approximately 25 times improvement in timing jitter. Concerning microwave optoelectronic applications, we demonstrate that a low phase noise oscillator can be obtained using a QD MLL integrated in an optical self injection loop without any opto-electronic or electro-optic conversion. A significant reduction of the -3 dB linewedith as low as 200Hz was obtained thanks to optimised tuning of the optical external cavity length. The phase noise has been reduced from -75dBc/Hz to a level as low as -105dBc/Hz at an offset of 100kHz. This yields to ultra low timing jitter and shows the potential to fabricate simple, and yet low noise oscillators based on semiconductor lasers without any high frequency electronics, photodetector or modulator. Finally, we report, for the first time, error-free transmission of 8 WDM channels over 50 km long single mode fiber at 10 Gbit/s using comb-generation in a quantum dash based mode locked laser. Such good performance paves the way for the use of mode locked-lasers in WDM transmission and allows considering such a solution in an integrated WDM transceiver
Agaisse, Romain. "Auto-affinement spectral laser assisté par effet Brillouin." Electronic Thesis or Diss., Université de Rennes (2023-....), 2023. http://www.theses.fr/2023URENS091.
Повний текст джерелаThe frequency stability of lasers is a sought-after property in many fields such as optical communications, spectroscopy and time-frequency metrology. In this context, the Foton Institute has developed a principle making it possible to spectrally self-narrow a laser at extremely low levels. For this we pump a non-reciprocal Brillouin resonator which generates a spectrally pure Stokes wave. The addition of a phase-locked loop which counter-reacts to the pump then makes it possible to avoid mode hops of the Brillouin resonator while spectrally narrowing the pump laser, thus producing a cascaded self-narrowing effect. In this manuscript, we theoretically and experimentally study the Brillouin assisted laser spectral self-narrowing system. The modeling of all of its constituents using the formalism of transfer functions is supported by experimental validations. These transfer functions account for the response of the different elements of the system to phase and amplitude fluctuations. The expression of the transfer function of the complete system is then validated experimentally by comparing the theoretical predictions to the open-loop transfer function measurements as well as in step response. Exploitation of the model and its adjustable physical parameters then makes it possible to further reduce frequency fluctuations for a solid-state pump laser emitting at 1.54 μm. This allows us in particular to highlight the fact that the Brillouin resonator in these phase-locking conditions plays the role of an optical reference. The performance of the system is then evaluated by duplicating it and measuring the beat between the two independent systems in the microwave domain. Finally, the “buffer reservoir” principle is added to the spectral narrowing system. This principle based on the insertion of a non-linear absorption mechanism in the pump laser makes it possible to reduce excess amplitude noise at relaxation oscillations by 32 dB. This eliminates the main source of amplitude noise converted into phase noise in the system
Akrout, Akram. "Contribution à l’étude des lasers à verrouillage de modes pour les applications en télécommunications." Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2009. http://www.theses.fr/2009TELE0023.
Повний текст джерелаThis PhD thesis deals with the integration of InP based quantum dash mode locked lasers for use in optical communication systems and microwave optoelectronic applications. The properties of pulse and characterization methods are described as well as requirements for application in communication systems. Experimental and analytic method for pulse “chirp” characterization and compensation are also discussed. In particular, we demonstrate that high order dispersion can be compensated using specific fibre length. The characterization of quantum dash based mode locked lasers, has shown their potential to generate high spectral purity self-pulsating signals, with state-of-the-art spectral linewidth of ~ 850 Hz. Especially, the importance of, and way to reduce high-frequency jitter is discussed. Indeed, a novel method for measurement of high-frequency jitter based on optical cross-correlation technique is implemented. Systematic investigation of 10 GHz passively mode locked laser based on InAs/InP quantum dashes emitting at 1.55 µm have demonstrated a reduced value of timing jitter of 500 fs in the 150 kHz – 320 MHz frequency range. Compared to typical passively mode-locked quantum well laser which exhibit timing jitter in the range 12 ps (150 kHz – 50 MHz), our device demonstrates an approximately 25 times improvement in timing jitter. Concerning microwave optoelectronic applications, we demonstrate that a low phase noise oscillator can be obtained using a QD MLL integrated in an optical self injection loop without any opto-electronic or electro-optic conversion. A significant reduction of the -3 dB linewedith as low as 200Hz was obtained thanks to optimised tuning of the optical external cavity length. The phase noise has been reduced from -75dBc/Hz to a level as low as -105dBc/Hz at an offset of 100kHz. This yields to ultra low timing jitter and shows the potential to fabricate simple, and yet low noise oscillators based on semiconductor lasers without any high frequency electronics, photodetector or modulator. Finally, we report, for the first time, error-free transmission of 8 WDM channels over 50 km long single mode fiber at 10 Gbit/s using comb-generation in a quantum dash based mode locked laser. Such good performance paves the way for the use of mode locked-lasers in WDM transmission and allows considering such a solution in an integrated WDM transceiver
Prakasha, Prarthana. "A Study of Injection Locking in Optoelectronic Oscillator." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/41147.
Повний текст джерелаHallal, Ayman. "Génération d'ondes millimétriques et submillimétriques sur des systèmes fibrés à porteuses optiques stabilisées." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S005/document.
Повний текст джерелаI report in this manuscript a theoretical and experimental study of a compact, reliable and low cost source of 30 Hz linewidth, continuous and coherent electromagnetic waves tunable from 1 GHz to 500 GHz in steps of 1 GHz. These waves are generated by photomixing two distributed feedback (DFB) laser diodes at 1550 nm which are frequency stabilized with orthogonal polarizations on the same optical fibered Fabry-Perot cavity. I have designed very fast electronic control filters for each laser allowing a 7 MHz servo bandwidth limited by the loop length. I demonstrate phase noise suppressions down to -60 dBc/Hz at 1 kHz and -90 dBc/Hz at 100 kHz offset frequencies from a 92 GHz electrical carrier. I also measure a ~170 kHz frequency drift of the beat note at 10 GHz on the long term over a continuous 7.5 hour locking period. I show an optimized design of an integrated servo loop of few tens of cm length which reduces the phase noise by 18 dB at 1 MHz optical carrier offset frequency and the phase-amplitude couplings in the cavity by a factor of 50 compared to the experimental one. The addition of a third DFB laser phase stabilized on a local oscillator allows the possibility to have continuously tunable source over 1 THz. The continuous wave source also makes it possible to generate fixed repetition rate pico- or femtosecond pulses from highly non-linear and dispersive fibers, replacing the DFB lasers by further stable lasers. I have calculated by simulation 7.2 fs temporal jitter at 40 GHz repetition rate over a 1 ms integration time
Buckley, David. "Phase-locked, multiple ridge waveguide, semiconductor laser arrays." Thesis, University of Bath, 1992. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334692.
Повний текст джерелаKao, Tsung-Yu. "Surface-emitting distributed feedback terahertz quantum-cascade phase-locked laser arrays." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54235.
Повний текст джерелаThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 111-114).
A new approach to achieve high-power, symmetric beam-pattern, single-mode THz emission from metal-metal waveguide quantum-cascade laser is proposed and implemented. Several surface-emitting distributed feedback terahertz lasers are coupled through the connection phase sectors between them. Through carefully choosing the length of phase sectors, each laser will be in-phase locked with each other and thus create a tighter beam-pattern along the phased-array direction. A clear proof of phase-locking phenomenon has been observed and the array can be operated in either in-phase or out-of-phase mode at different phase sector length. The phase sector can also be individually biased to provide another frequency tuning mechanism through gain-induced optical index change. A frequency tuning range of 1:5 GHz out of 3:9 THz was measured. Moreover, an electronically controlled "beam steering" device is also proposed based on the result of this work. This thesis focuses on the design, fabrication and measurement of the surface-emitting distributed feedback terahertz quantum-cascade phase-locked laser arrays.
by Tsung-Yu Kao.
S.M.
Wang, Long. "Talbot Imaging in Multi-mode Optical Fibers with Periodic Multiple Sub-apertures." University of Dayton / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1322777852.
Повний текст джерелаHarvey, David. "Automatically phase-locked fibre optic electronic speckle pattern interferometry using laser vibrometry." Thesis, Heriot-Watt University, 1996. http://hdl.handle.net/10399/715.
Повний текст джерелаPanapakkam, Venkatesan Vivek. "Optical frequency comb generation using InP based quantum-dash/ quantum-well single section mode-locked lasers." Thesis, Evry, Institut national des télécommunications, 2016. http://www.theses.fr/2016TELE0024/document.
Повний текст джерелаThe increasing demand for high capacity, low cost, high compact and energy efficient optical transceivers for data center interconnects requires new technological solutions. In terms of transmitters, optical frequency combs generating a large number of phase coherent optical carriers are attractive solutions for next generation datacenter interconnects, and along with wavelength division multiplexing and advanced modulation formats can demonstrate unprecedented transmission capacities. In the framework of European project BIG PIPES (Broadband Integrated and Green Photonic Interconnects for High-Performance Computing and Enterprise Systems), this thesis investigates the generation of optical frequency combs using single-section mode-locked lasers based on InAs/InP Quantum-Dash and InGaAsP/InP Quantum-Well semiconductor nanostructures. These novel light sources, based on new active layer structures and cavity designs are extensively analyzed to meet the requirements of the project. Comprehensive investigation of amplitude and phase noise of these optical frequency comb sources is performed with advanced measurement techniques, to evaluate the feasibility of their use in high data rate transmission systems. Record Multi-Terabit per second per chip capacities and reasonably low energy per bit consumption are readily demonstrated, making them well suited for next generation datacenter interconnects
Panapakkam, Venkatesan Vivek. "Optical frequency comb generation using InP based quantum-dash/ quantum-well single section mode-locked lasers." Electronic Thesis or Diss., Evry, Institut national des télécommunications, 2016. http://www.theses.fr/2016TELE0024.
Повний текст джерелаThe increasing demand for high capacity, low cost, high compact and energy efficient optical transceivers for data center interconnects requires new technological solutions. In terms of transmitters, optical frequency combs generating a large number of phase coherent optical carriers are attractive solutions for next generation datacenter interconnects, and along with wavelength division multiplexing and advanced modulation formats can demonstrate unprecedented transmission capacities. In the framework of European project BIG PIPES (Broadband Integrated and Green Photonic Interconnects for High-Performance Computing and Enterprise Systems), this thesis investigates the generation of optical frequency combs using single-section mode-locked lasers based on InAs/InP Quantum-Dash and InGaAsP/InP Quantum-Well semiconductor nanostructures. These novel light sources, based on new active layer structures and cavity designs are extensively analyzed to meet the requirements of the project. Comprehensive investigation of amplitude and phase noise of these optical frequency comb sources is performed with advanced measurement techniques, to evaluate the feasibility of their use in high data rate transmission systems. Record Multi-Terabit per second per chip capacities and reasonably low energy per bit consumption are readily demonstrated, making them well suited for next generation datacenter interconnects
Liu, Ling. "Analysis and experimental demonstration of conformal adaptive phase-locked fiber array for laser communications and beam projection applications." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8773.
Повний текст джерелаThesis research directed by: Dept. of Electrical and Computer Engineering Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Finelli, Stefano. "Realizzazione di un sistema di stabilizzazione per laser a stato solido, per la generazione di luce squeezed in esperimenti di interferometria." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8296/.
Повний текст джерелаTurghun, Matniyaz. "Free-space NPR mode locked erbrium doped fiber laser based frequency comb for optical frequency measurement." Thesis, Kansas State University, 2014. http://hdl.handle.net/2097/18682.
Повний текст джерелаDepartment of Physics
Brian R. Washburn
This thesis reports our attempt towards achieving a phase stabilized free-space nonlinear polarization rotation (NPR) mode locked erbium doped fiber laser frequency comb system. Optical frequency combs generated by mode-locked femtosecond fiber lasers are vital tools for ultra-precision frequency metrology and molecular spectroscopy. However, the comb bandwidth and average output power become the two main limiting elements in the application of femtosecond optical frequency combs. We have specifically investigated the free-space mode locking dynamics of erbium-doped fiber (EDF) mode-locked ultrafast lasers via nonlinear polarization rotation (NPR) in the normal dispersion regime. To do so, we built a passively mode-locked fiber laser based on NPR with a repetition rate of 89 MHz producing an octave-spanning spectrum due to supercontinuum (SC) generation in highly nonlinear fiber (HNLF). Most significantly, we have achieved highly stable self-starting NPR mode-locked femtosecond fiber laser based frequency comb which has been running mode locked for the past one year without any need to redo the mode locking. By using the free-space NPR comb scheme, we have not only shortened the cavity length, but also have obtained 5 to 10 times higher output power (more than 30 mW at central wavelength of 1570 nm) and much broader spectral comb bandwidth (about 54 nm) compared to conventional all-fiber cavity structure with less than 1 mW average output power and only 10 nm spectral bandwidth. The pulse output from the NPR comb is amplified through a 1 m long EDF, then compressed by a length of anomalous dispersion fiber to a near transform limited pulse duration. The amplified transform limited pulse, with an average power of 180 mW and pulse duration of 70 fs, is used to generate a supercontinuum of 140 mW. SC generation via propagation in HNLF is optimized for specific polling period and heating temperature of PPLN crystal for SHG around 1030 nm. At last, we will also discuss the attempt of second harmonic generation (SHG) by quasi phase matching in the periodically polled lithium niobate (PPLN) crystal due to nonlinear effect corresponding to different polling period and heating temperature.
Rzaigui, Habeb. "Systèmes hybrides opto/sans fil pour les réseaux multi-gigabits aux fréquences millimétriques." Thesis, Université Grenoble Alpes (ComUE), 2016. http://www.theses.fr/2016GREAT014/document.
Повний текст джерелаThis thesis focuses on the radio-over-fiber (RoF) communication systems at millimeter frequencies in the frequency range 57-66 GHz and optical generation of a signal at millimeter-wave frequency band. The technique used is based on mode-locked laser diodes. The diodes employed in this work are in quantum dots (or quantum dashes) technology. In this thesis, several studies were conducted: the first relates the ability of integration these types of lasers in the RoF communication systems under direct or external modulation. The second study was devoted to propagation effects. An original technique was implemented to reduce the sensitivity to chromatic dispersion in an optical fiber. A study of the reduction of phase noise mode-locked lasers based on the observation of the reaction effect and against the external optical injection was presented
Specht, Hendrik. "MEMS-Laser-Display-System." Doctoral thesis, Universitätsbibliothek Chemnitz, 2011. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-71334.
Повний текст джерелаSpecht, Hendrik. "MEMS-Laser-Display-System: Analyse, Implementierung und Testverfahrenentwicklung." Doctoral thesis, Universitätsverlag der Technischen Universität Chemnitz, 2010. https://monarch.qucosa.de/id/qucosa%3A19558.
Повний текст джерела黃信耀. "Study of Steady Active Mode-Locked Fiber Lasers by Using Phase-Locked Loop." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/70169386389707074303.
Повний текст джерела國立清華大學
光電工程研究所
93
Abstract In recent year, optical communication becomes more and more important, especially in long distance network communication. The optical sources play an important rule in the system. Fiber optical transmission using a short optical pulse train is a fundamental technology in order to achieve a high-speed and long-distance global network. For ultra-high speed fiber optical communication, the characteristic of ideal transmission source is demanded to be stable (low amplitude jitter), widely tunable wavelength, transform limited, low timing jitter, adjustable pulsewidth, and high extinction ratio. Therefore, a mode-locked erbium-doped fiber lasers (ML-EDFLs) source with high repetition rate and short pulse width is good selection than semiconductor lasers for ultrahigh-speed communication system. Besides, these ML-EDFLs can produce higher output power and lower insertion loss in all fiber system. In recent paper, they mention some methods to solve the problem of stability of the optical mode-locked fiber laser systems, but it needs some more device or high frequency circuit. In this thesis, we use phase locked loop to make the system stable. And the final result improved by PLL.
Lin, ssu chin, and 林世軒. "Towards Optoelectronic Phase-locking of CW Semiconductor Lasers and Femtosecond Mode-locked Laser for THz Frequency Metrology." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/15311405019585562045.
Повний текст джерела國立交通大學
光電工程所
91
We characterize the phase-locking between dual-wavelength cw semiconductor laser and mode-locked pulse laser. Through biting signal from dipole antenna generated by two various wavelength cw lasers, semiconductor laser could be locked to high order harmonic frequency of repetition rate of mode locked laser was demonstrated. In this thesis, our experiment is be to divided into two parts, part one : we success to depressed timing jitter of mode-locked laser from 7.5ps to 880fs. Part two : We use the harmonic frequency of mode-locked laser as the standard of dual-wavelength cw semiconductor laser and to stabilize the frequency of laser diode .We depress the frequency fluctuation of laser diode from 100MHz to 4~10MHz.
Lee, Wen-Chin, and 李文進. "A 10GHz PLL Phase Shifter Based Circuitry for Frequency Stabilization and Delay-Time Tuning of Mode-Locked Fiber Lasers." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/54492355150402907070.
Повний текст джерела國立交通大學
電機資訊學院碩士在職專班
92
With the evolution of modern electronic technology and communication system came the need to provide stable oscillation and continuous phase shift at particular frequencies. Continuously tuning the phase of microwave signal or optical clock via optical or optoelectronic technique has been extensively studied since its particular applications in phased-array antennas (PAAs), wireless/fiber communication and electro-optic sampling (EOS) system. In this thesis, we demonstrate a 10GHz electronic type digital phase locked loop with phase shifter (DPLL-PS) based circuitry for frequency stabilization and delay-time tuning of mode-locked fiber lasers. We propose the electronic type DPLL-PS to establish the phase continuous tunable, operation easily and high phase lock stability and especially to improve the drawback of limited bandwidth up to Ku band range. This thesis consists of three main parts: the first introduces the concept of phase locked loop and operation principle of phase shifter. The second part describes briefly the methods of mode-locked fiber lasers. The third part demonstrates the implementation and test results. In our research, the maximum phase deviation is up to 723o under the change in controlling voltage of 8.0 volts, which is completely independent of operating frequency. A linear transferred function of the DPLL-PS with responsivity of 90.375 o/volt was measured. The phase fluctuation of the DPLL-PS can be as small as 0.022o.
"Phase-locked semiconductor quantum well laser arrays." Massachusetts Institute of Technology, Research Laboratory of Electronics, 1987. http://hdl.handle.net/1721.1/4217.
Повний текст джерелаAlso issued as Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1987.
Includes bibliographical references.
Supported in part by the Joint Services Electronics Program. DAAL03-86-K-0002 Supported in part by the National Science Foundation. ECS 83-05448 Supported in part by the U.S. Army Research Center. P-23223-EL
LIU, HAO-WEI, and 劉皓維. "Nonlinear Phase Effects In Cascaded Mode-Locked Nd:YVO4 Laser." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/827jp9.
Повний текст джерелаZHANG, ZHONG-DAO, and 張仲道. "Use phase lock loop to reduce timing jitter of Nd:YAG CW mode-locked laser." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/87809560913642115565.
Повний текст джерелаJyh-Wei, Lin, and 林智偉. "Self-Phase Modulation and Fast Switching Enhanced Pulse Generation in an Actively Mode-Locked Nd:YLF Laser." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/63493350454865970615.
Повний текст джерела國立中山大學
光電工程學研究所
86
Synthesized high-speed pulse generator was employed to drive an acousto-optic modulator in an AM mode-locked Nd:YLF laser. The result shown that pulsegenerated shorter than 10 ps at a repetition rate of 200 MHz with an average output power of 600 mW. A close form model based on gaussian approximation was built toestimate pulse width. A complete time domain model was used to study pulseevolution in AM mode-locked laser with self-phase modulation. Both self-phase modulation and fast switching enhanced pulse-shaping ability were primary causes for the low ratio between pulse-width and repetition rate. Using these effects we canreduce pulse width without increasing modulation frequency. This indicates that the laser provides an useful application for time domain optoelectronic samplingmeasurement on microwave/millimeter-wave circuits and devices.
Lee, Chia-Yu, and 李佳育. "Phase retrieval ultrafast waveform analysis of soft-aperture Kerr-lens mode-locked laser by using Genetic algorithms." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/41604059942375070414.
Повний текст джерела國立交通大學
光電工程所
89
A Kerr-lens mode-locking (KLM) laser usually relies on soliton-like pulse shaping effect from interplay between the self phase modulation (SPM) and the group velocity dispersion (GVD) to generate ultra-short pulses. Sometimes, nonlinear chirp generated in the leading and trailing edge of pulse could not be fully compensated by GVD and then the pulse splitting below 1ps was observed in Ti:sapphire laser. Besides, another kind of multiple pulses with nanosecond asymmetric spacing between pulses was also reported. To understand the reason why these phenomena occurred, chirp is the most important information needs to know. Thus we use two and one interference autocorrelator and make use of Genetic Algorithms (GA) analysis to calculate phase of pulse. GA is one of the non-constrained mathematical optimization theories based on the evolution theory in the biology (survival of the fitness). It finds a near-global optimization solution based on four steps including encode, selection, crossover, and mutation. Through the phase retrieval, the chirp of pulse splitting in a Kerr-lens mode-locked Ti:sapphire laser were investigated. It also shows nonlinear chirp generated in the leading and trailing edge of pulse could not be fully compensated by GVD is the cause of pulse splitting.
Li, Yong-De, and 李勇德. "Polarization Maintaining Mode-locked Er-doped Fiber Laser Based on a Nonlinear Fiber Loop with Active Phase Modulation." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/76437039200624973617.
Повний текст джерела國立交通大學
光電工程研究所
104
In this thesis work we mainly study the polarization maintaining mode-locked Er-doped fiber laser based on a nonlinear fiber loop. Since the initial passive mode-locked laser setup can only generate noise-like pulses, we insert a phase modulator in the nonlinear fiber loop to adjust the nonlinear fiber loop transmission by tuning the modulation amplitude of the phase modulator. Single pulse mode-locking is successfully achieved. To further improve the mode-locking performance and to increase the possible mode-locking states, we remove the optical band-pass filter in the main fiber loop. After this change, we can observe the harmonic mode-locking at 2, 4, 6, 8, 10 and 12 GHz, and the rational harmonic mode-locking at 2, 5 and 10 GHz. We can also observe that the center lasing wavelength will be shifted if the modulation frequency is slight tuned. The relative ratio between the wavelength tuning range and the modulation frequency tuning range can be used to estimate the net dispersion in the fiber laser cavity. By inserting a suitable section of dispersion compensation fibers, we finally achieve the shortest ps pulse width from the studied fiber laser setup.
Chih-Shang, Liu. "Study of Integrating Fiber and Optical Satellite Communication System with Applying Phase Modulated Figure Eight Mode-Locked Fiber Laser." 2003. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0021-2603200719140735.
Повний текст джерелаYu-Wei, Yang. "Study of High Speed Pulse Transmission with Applying Amplitude Modulated and Phase Modulated Figure Eight Mode-Locked Fiber Laser." 2004. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0021-2004200711384222.
Повний текст джерелаLiu, Chih-Shang, and 劉志祥. "Study of Integrating Fiber and Optical Satellite Communication System with Applying Phase Modulated Figure Eight Mode-Locked Fiber Laser." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/46889026303577753265.
Повний текст джерела國立臺灣師範大學
光電科技研究所
92
In this thesis, we propose a fiber-satellite integration using a high speed phase-modulated mode-locked figure-eight laser and transmission system. In the cavity of high speed laser source, we utilize a phase modulator to inject additive modulation signal. The modulation signal can let the longitudinal mode in cavity produce constructive interference, and then, achieve small modulation signal to excite harmonic and rational mode-locked laser in high repetition rate. After producing high speed mode-locked laser, we do detuning the modulation parameters to analyze the effect of repetition rate, pulsewidth, rise time, falling time and jitter. In optical transmission systems, we consider the integration of long-distance fiber transmission and wireless optical satellite communication. 100 km long single mode fiber is used in the long-distance fiber transmission analysis. We also insert the fiber Bragg grating to compensate chromatic dispersion. In optical satellite communication system, we consider the impact of weather, beam divergence angle and so on. We evaluate the conditions and search the optimal parameters in long-distance and optical satellite integrated transmission for looking for the optimum efficiency.
Yang, Yu-Wei, and 楊有為. "Study of High Speed Pulse Transmission with Applying Amplitude Modulated and Phase Modulated Figure Eight Mode-Locked Fiber Laser." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/42434853263212767215.
Повний текст джерела國立臺灣師範大學
光電科技研究所
93
In this thesis, we propose a fiber-satellite integration using a high speed AM fed amplitude-modulated mode-locked and AM/PM fed phase-modulated mode-locked figure-eight laser apply to transmission system. In the cavity of high speed laser source, we utilize an amplitude modulator and phase modulator to inject additive modulation signal respectively. The modulation signal can let the longitudinal mode in cavity produce constructive interference, and then, achieve small modulation signal to excite harmonic and rational mode-locked laser in high repetition rate. After producing high speed mode-locked laser, we do detuning the modulation parameters to analyze the effect of repetition rate, pulsewidth, rise time, falling time and jitter. In optical transmission systems, we consider the 100 km long single mode fiber is used in the fiber transmission analysis. We also insert the dispersion-compensated fiber to compensate chromatic dispersion, and analyse eye pattern with various transmission system, we can evaluate proper application for our designed system.
Chiu, Jin-Chen, and 邱金城. "Study on Nonlinear Self-Phase Modulation Enhancement in Passive Mode Locked Fiber Laser with Single-Wall Carbon Nanotube Saturable Absorber." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/22147616970849188470.
Повний текст джерела國立中山大學
光電工程學系研究所
99
The dependence of thickness and concentration product (TCP) of single-wall carbon nanotubes saturable absorber (SWCNTs SA) on stabilizing and shortening pulse width in passively mode-locked erbium-doped fiber ring laser (MLEDFL) was investigated and measured. The TCP represented the amounts of SWCNTs, which the optical beam encountered when passing through the SWCNTs SA. If the TCP was smaller than 8.25 (μm x wt%), the spectral bandwidth was below 2 nm. The pulse shaping was dominated by its own self amplitude modulation (SAM) of SWCNTs SA. With further increasing TCP, the soliton-like ML operation was achieved and the spectral bandwidth was expanded to 6 nm. For soliton-like mode locking (ML) operation, the area theorem dominated the pulse shaping. Through area theorem analysis, the estimation of SPM increased as the TCP increased. The adequate enhanced SPM for balancing the slight negative GVD was provided to generate soliton-like ML pulses shorten the pulse width. However, as the TCP increased, the soliton pulse energy decreased. The decreasing soliton pulse energy restricted the further pulse shortening. The results showed that the dependence of the pulse energy and nonlinear self phase modulation (SPM) on TCP enabled to determine the shortest pulse width in MLEDFL based on the area theorem. At optimized TCP of 70.93 (μm x wt%), it was found that the shortest pulse width of 418 fs. In addition, based on the estimated SPM from area theorem, the nonlinear refractive index n2 was calculated at the level of 0.4 - 1 x 10^-15 m^2/W that was close to the literature values of 10^-15 - 10^-16 m2/W. It provides another way to estimate the nonlinear refractive index except for the Z-scan measurement. We could also estimate the SPM if an active Z-scan measurement was taken to obtain the nonlinear refractive index of the sample. We realized the trend of pulse energy through few samples in MLEDFL, the behavior of pulse width could be theoretically simulated based on area theorem. Hence, with the area theorem analysis, the optimized TCP of SWCNTs SA could be simulated and estimated to generate the shortest pulse width from the trends of pulse energy and estimated SPM. The significant effect of TCP on pulse energy, SPM, pulse width, and spectral bandwidth of MLFLs suggests that the TCP represents the total amount of SWCNTs in SA, which can be used as one of key parameters for characterizing the passive MLFL pulse width. Through the study of the dependence of TCP on ML pulses in MLEDFL, it may provide a guideline to fabricate an effective SWCNTs SA to generate the shortest pulse width of the MLEDFL.
Wu, Ming-Chung, and 吳銘忠. "Suppression of Phase Noise and Supermode Noise in Mode-Locked Erbium Doped Fiber Laser with an Intra-Cavity Semiconductor Optical Amplifier." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/33890655394264584669.
Повний текст джерела國立交通大學
光電工程系所
93
In this thesis, we demonstrate that the ultralow supermode noise and single-sided-band (SSB) phase noise characteristics of a harmonically mode-locked (HML) Erbium-doped fiber laser (EDFL) with an intra-cavity semiconductor optical amplifier (SOA) and optical band-pass filter (OBPF) are investigated, and are compared to a mutually injection-mode-locking (IML) link of gain-switched Fabry-Perot laser Diode (FPLD) and EDFL with the state-of-the-art performances. With an intra-cavity SOA based high-pass filter driven at unitary gain condition, we primarily demonstrate that the supermode noise suppression ratio (SMNSR) of the HML-EDFL can be simultaneously suppressed to be comparable with that of the FPLD-IML-EDFL without sacrificing the SSB phase noise and jitter performances. The SOA operated at nearly transparent condition enhances the SMNSR of the EDFL to 86 dB at the cost of degrading phase noise (-104.2 dBc/Hz), increasing jitter (1.4 ps), and broadened pulsewidth (61 ps). By adding an OBPF into the ring cavity, the SMNSR, SSB phase noise, jitter and pulsewidth of the SOA filtered HML-EDFL can further be improved to 90 dB, -112 dBc/Hz, 0.7 ps and 42 ps, respectively. The SMNSR performance of the HML-EDFL with SOA and OBPF has already been comparable with that of a FPLD-IML-EDFL link. At last, we use phase lock loop (PLL) and piezo-electric transducer (PZT) controller link to achieve regenerative mode-locked EDFL technique. The SSB phase noise and timing jitter are further analyzed in this experiment.
Hung, Chih-Hao, and 洪智皓. "10 GHz mode-locked Er-doped fiber laser based on an all-PM fiber loop with in-loop phase modulation and the high-speed wavelength-swept application." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/gtfdwe.
Повний текст джерела國立交通大學
光電工程研究所
105
In this thesis work, we mainly utilize the polarization maintaining fibers for constructing the mode-locked fiber lasers. The gain fiber we use is the Er-doped fiber and an EO phase modulator is inserted into the optical fiber loop for active mode-locking. The travelling phase modulator can adjust the phase bias of the fiber loop and as a result, it can also change the fiber loop transmission. By suitably selecting the modulation frequency of the phase modulator, we successfully realize active mode-locking at the 10 GHz high repetition rate through the harmonic mode-locking technique. In addition, we use a voltage tuning dielectric resonator oscillator (DRO) as the 10 GHz signal generator to sweep the modulation frequency. We successfully achieve a 10 GHz high repetition rate mode-locked Er-doped fiber laser with high-speed optical wavelength sweeping capability. The widest sweep range is about 25 nm when the sweep rate is about 8.5 kHz.