Thesis (M.S.)--University of Alabama at Birmingham, 2008. / Description based on contents viewed Feb. 10, 2009; title from PDF t.p. Includes bibliographical references (p. 33).

Thesis (doctoral)--University of Oulu, 2004. / Includes bibliographical references (p. 147-171). Also available on the World Wide Web.

Thesis (M. Phil.)--University of Hong Kong, 1998. / Includes bibliographical references.

<p>Asymmetric multiple quantum wells (AMQWs) can provide broad and flat gain spectra. Broadly tunable diode lasers can be realized with AMQW active regions and without the need for antireflection coatings on cleaved facets.</p> <p> This thesis reports the application of AMQW broadly tunable lasers with uncoated facets for Fourier domain and synthesized optical coherence tomography (OCT). A depth resolution of 13 μm in air was obtained with a test bed OCT system that used diffractive optical elements, short external cavities, and AMQW InGaAsP/InP broadly tunable lasers as the light sources for the Fourier domain and the synthesized OCT measurements. The centre wavelengths of the broadly tunable sources were 1550 nm and the tunable ranges were ≤ 117 nm.</p> <p>The features of broad and flat gain spectra of AMQWs also make AMQWs ideal candidates for broad spectral width superluminescent diodes (SLDs). 1300 nm AMQW InGaAsP/InP SLDs were designed and fabricated for application to time domain OCT. For the design of the active region, it was found by simulation of gain and the comparison of two growths that the transition carrier density (TCD) has to be reasonably high to achieve high power SLDs. A transfer matrix method was used to solve for the modes of planar optical waveguides with arbitrary layers and the thicknesses of these layers were optimized with a Marquardt nonlinear fitting method. With the optimization of the optical waveguide and with AMQWs with high TCDs, the output power of SLDs could reach 2 mW with > 90 nm spectral width. It is shown by time domain OCT measurements that the depth resolution of the OCT measurements could reach 7.85 μmin air with double section SLDs.</p> <p>Two dimensional OCT images of a glass cover slip were built with the imageSC function in Matlab™. Image enhancement with blind/not-blind deconvolution was performed based on the measured point spread function (PSF) of the OCT setup. A Richardson-Lucy algorithm was used as the blind deconvolution method and a not-blind version of a Jansson-Van Cittert method was used.</p> / Thesis / Doctor of Philosophy (PhD)

Thesis (MSc)--University of Stellenbosch, 2003. / ENGLISH ABSTRACT: The efficient manipulation of various nonlinear optical processes frequently requires the shaping of the laser beams used for these processes. Three beam shaping techniques were investigated in this thesis. The focussing of Gaussian laser beams was investigated analytically, in order to efficiently manipulate the focussed beam characteristics. The beam-shaping characteristics of a diffractive optical element (DOE) was investigated numerically, which illustrates the beamshaping capability of the DOE, and identifies the critical parameters in experimental situations. The use of a waveguide as beam shaping device was investigated analytically and experimentally, and characterized for use with the available tunable laser sources. A Raman laser, or Raman shifter, employs stimulated vibrational Raman scattering to generate laser radiation at shifted frequencies. The waveguide was successfully applied as a beam shaping device in the Raman laser system, for optimisation of the process. The Raman laser system was investigated experimentally and characterized for use with the available tunable laser sources. The successful generation of laser radiation at shifted frequencies illustrates the usefulness of the system for generating tunable red-shifted frequencies. The results of this work allow the simple and efficient application of the Raman laser to generate laser radiation at shifted frequencies, in particular tunable infrared laser radiation which is desirable for molecular spectroscopy. / AFRIKAANSE OPSOMMING: Nie-liniêre optiese prosesse kan meer effektief benut word deur die vervorming van die laserbundels wat gebruik word in die prosesse. In hierdie tesis word drie laserbundel-vervormings tegnieke ondersoek. Die fokussering van Gaussiese laserbundels word analities ondersoek, om die gefokusseerde bundel se eienskappe effektief te manipuleer. Die bundel-vervormings eienskappe van ’n diffraktiewe optiese element word numeries ondersoek, wat die effektiwiteit van die bundelvervorming en die sensitiewe parameters in die sisteem uitwys. Die gebruik van ’n golfgeleier as ’n bundel-vervormings tegniek word ook analities en eksperimenteel ondersoek, en gekarakteriseer vir gebruik met die gegewe golflengte-verstelbare laser sisteme. ’n Raman laser, wat gestimuleerde vibrasionele Raman verstrooiing gebruik om laser lig te genereer by Stokes-verskuifde frekwensies, word ondersoek. Die golfgeleier word effektief gebruik as ’n bundel-vervormings tegniek in die Raman laser, om die bogenoemde nie-liniêre proses te optimeer. Die Raman laser was eksperimenteel ondersoek en gekarakteriseer vir gebruik met die gegewe golflengte-verstelbare lasers. Laser lig by verskuifde golflengtes is suksesvol gegenereer, wat die bruikbaarheid van die sisteem illustreer. Van belang is spesifiek verstelbare infrarooi laser lig, wat gebruik kan word in die laser-spektroskopie van molekules. Die resultate van hierdie werk lei tot die eenvoudige en effektiewe gebruik van die Raman laser, om langer golflengtes in die infrarooi gebied te genereer met ’n gegewe laser in die sigbare gebied.

by Hung Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 69-[73]). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- All Optical Multi-Access Network --- p.1 / Chapter 1.2 --- Multi-access Techniques --- p.2 / Chapter 1.2.1 --- Wavelength-Division Multi-access (WDMA) --- p.2 / Chapter 1.2.2 --- Subcarrier Multi-Access (SCMA) --- p.3 / Chapter 1.2.3 --- Time-Division Multi-Access(TDMA) --- p.3 / Chapter 1.3 --- Numerical Modelling of Semiconductor Mode-locked laser --- p.4 / Chapter 1.4 --- Objective of this Thesis --- p.5 / Chapter 2 --- Optical TDMA networks --- p.7 / Chapter 2.1 --- Introduction --- p.7 / Chapter 2.2 --- OTDM --- p.8 / Chapter 2.3 --- Network Architecture --- p.9 / Chapter 2.3.1 --- Broadcast Networks --- p.9 / Chapter 2.3.2 --- Switch-based networks --- p.10 / Chapter 2.4 --- Key technologies for optical TDMA Network --- p.13 / Chapter 2.4.1 --- High Repetition Rate Short Pulse sources --- p.13 / Chapter 2.4.2 --- Multiplexer and de-multiplexers --- p.15 / Chapter 2.4.3 --- Optical Clock Recovery --- p.17 / Chapter 2.4.4 --- All optical logic gates --- p.18 / Chapter 2.5 --- Summary --- p.19 / Chapter 3 --- A Channel-Tunable Mode-locked Laser Transmitter for OTDM Networks --- p.20 / Chapter 3.1 --- Introduction --- p.20 / Chapter 3.2 --- Principle of Operation --- p.21 / Chapter 3.3 --- Experimental Demonstration --- p.23 / Chapter 3.4 --- The Channel Tuning Transient --- p.25 / Chapter 3.5 --- Experimental Investigation of channel-tuning transient --- p.28 / Chapter 3.6 --- Summary --- p.37 / Chapter 4 --- Modeling of Mode-Locked Semiconductor Laser --- p.38 / Chapter 4.1 --- Introduction --- p.38 / Chapter 4.2 --- Principle of Mode-Locking --- p.39 / Chapter 4.3 --- Simulation Model --- p.41 / Chapter 4.3.1 --- Travelling Wave Rate Equation Analysis --- p.41 / Chapter 4.3.2 --- Large Signal Time Domain Mode-locked Laser Model --- p.42 / Chapter 4.3.3 --- Modeling of Spontaneous Noise --- p.44 / Chapter 4.3.4 --- Modeling of Self-phase Modulation --- p.44 / Chapter 4.3.5 --- Frequency Dependent Gain Profile --- p.45 / Chapter 4.3.6 --- Computation Procedure --- p.45 / Chapter 4.4 --- Device Parameters --- p.47 / Chapter 4.5 --- Simulation Results on Passive Mode-locking --- p.48 / Chapter 4.5.1 --- Pulse Repetition Rate under Passive Mode-locking --- p.48 / Chapter 4.5.2 --- The effect of Differential Gain and Differential Absorption on Mode-locking Regimes --- p.50 / Chapter 4.5.3 --- The Effects of Linewidth Enhancement Factor and Ab- sorber Carrier Lifetime on Mode-locking Pulse Width --- p.53 / Chapter 4.6 --- Simulation Results on Hybrid and Subharmonic Mode-locking --- p.54 / Chapter 4.6.1 --- Modeling the Effect of Modulation on Absorber Section --- p.54 / Chapter 4.6.2 --- Modulation Phase Change Dynamics --- p.55 / Chapter 4.6.3 --- Subharmonc Mode-Locking Induced Amplitude Modulation --- p.62 / Chapter 4.7 --- Summary --- p.64 / Chapter 5 --- Conclusion --- p.66 / Chapter 5.1 --- Summary of the Thesis --- p.66 / Chapter 5.2 --- Future Work --- p.67 / Bibliography --- p.69

Chen Fei. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (leaves 86-92). / Abstracts in English and Chinese. / Acknowledgements --- p.i / List of publications --- p.ii / Abstract (In English) --- p.iii / Abstract (In Chinese) --- p.v / Table of contents --- p.vii / List of figures --- p.x / List of tables --- p.xiv / Chapter Chapter I --- Introduction --- p.1 / Chapter Chapter II --- Sol-gel channel waveguides --- p.6 / Chapter 2.1 --- General sol-gel process --- p.6 / Chapter 2.2 --- Dye-doped sol-gel zirconia and zirconia-ORMOSIL materials --- p.10 / Chapter 2.3 --- Fabrication of sol-gel channel waveguides --- p.15 / Chapter 2.3.1 --- General process of the photolithographic technique --- p.15 / Chapter 2.3.2 --- Channels in glass substrates by using photolithographic wet etching technique --- p.19 / Chapter 2.3.3 --- Channels in fused silica substrates by using photolithographic dry etching technique (Inductive-coupled plasma etching) --- p.24 / Chapter Chapter III --- Coupled-wave theory and experimental setup of distributed feedback channel waveguide lasers --- p.27 / Chapter 3.1 --- Coupled-wave theory of distributed feedback lasers --- p.27 / Chapter 3.2 --- Experimental setup --- p.33 / Chapter Chapter IV --- One-dimensional and two-dimensional optical waveguide analysis --- p.37 / Chapter 4.1 --- 1-D planar waveguide analysis --- p.37 / Chapter 4.2 --- 2-D channel waveguide analysis using the Marcatili method --- p.39 / Chapter 4.2.1 --- The Eypq modes: Polarization in the y direction --- p.42 / Chapter 4.2.2 --- The Eypq modes: Polarization in the x direction --- p.46 / Chapter 4.3 --- 2-D channel waveguide analysis using the effective index method --- p.48 / Chapter Chapter V --- Distributed feedback channel waveguide lasers tunable in the visible --- p.50 / Chapter 5.1 --- Rhodamine 6G-doped zirconia planar and channel waveguides --- p.51 / Chapter 5.2 --- Results and discussion --- p.56 / Chapter 5.3 --- Summary --- p.66 / Chapter Chapter VI --- Near infrared distributed feedback channel waveguide lasers --- p.68 / Chapter 6.1 --- LDS dye-doped zirconia-ORMOSIL planar and channel waveguides --- p.68 / Chapter 6.2 --- Results and discussion --- p.72 / Chapter 6.3 --- Summary --- p.80 / Chapter Chapter VII --- Summary --- p.81 / References --- p.86

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

Wang Jun. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2003. / Includes bibliographical references (leaves 74-79). / Abstracts in English and Chinese. / Acknowledgements --- p.i / List of publications --- p.ii / Abstract (In English) --- p.iii / Abstract (In Chinese) --- p.v / Table of contents --- p.vii / List of figures --- p.x / List of tables --- p.xiv / Chapter Chapter I --- Introduction --- p.1 / Chapter Chapter II --- Dye-doped sol-gel zirconia and zirconia-organically modified silicate waveguides --- p.6 / Chapter 2.1 --- General sol-gel process --- p.6 / Chapter 2.2 --- Dye-doped sol-gel zirconia and zirconia-ORMOSIL waveguides --- p.7 / Chapter Chapter III --- Basic theory and experiment setup of distributed feedback waveguide lasers --- p.13 / Chapter 3.1 --- Coupled-wave theory of distributed feedback lasers --- p.13 / Chapter 3.2 --- Introduction on the theory of planar optical waveguide --- p.16 / Chapter 3.3 --- Experiment setup design of DFB waveguide lasers --- p.19 / Chapter Chapter IV --- Zirconia and zirconia-organically modified silicate distributed feedback waveguide lasers tunable in the visible --- p.23 / Chapter Chapter V --- Tunable multi-wavelength distributed feedback zirconia waveguide lasers --- p.35 / Chapter 5.1 --- Brief introduction on multi-wavelength lasers --- p.35 / Chapter 5.2 --- R6G-doped zirconia multi-mode waveguides --- p.36 / Chapter 5.3 --- Experimental results and discussion --- p.39 / Chapter 5.3.1. --- Dual- and quadruple-wavelength DFB waveguide lasers --- p.39 / Chapter 5.3.2. --- The dispersion characteristics of multi-wavelength DFB waveguide lasers --- p.44 / Chapter 5.3.3. --- Determination of waveguide parameters by the DFB technique --- p.48 / Chapter 5.4 --- Summary --- p.51 / Chapter Chapter VI --- Distributed feedback laser action in sol-gel glass symmetric waveguides --- p.53 / Chapter 6.1 --- The fabrication of dye-doped glass symmetric waveguides --- p.54 / Chapter 6.2 --- Experimental results and discussion --- p.56 / Chapter 6.2.1. --- DFB laser action in sol-gel glass symmetric-asymmetric waveguide --- p.56 / Chapter 6.2.2. --- Dispersion characteristics of DFB symmetric and asymmetric waveguide lasers --- p.61 / Chapter 6.3 --- Summary --- p.65 / Chapter Chapter VII --- Summary --- p.69 / References --- p.74

Diode lasers have many advantages such as small size, high efficiency and small angular dispersion of the collimated beam. However they also have some problems like lack of frequency stability. They can not be tuned in wavelength. An external cavity can solve these problems and decrease the laser linewidth. To obtain a tunable, narrow linewidth light source, antireflection coatings were applied to commercial diode lasers which were then tested in an external cavity. Laser characteristics, such as threshold current, spectral behavior, I-V-curves, tuning range, and bandwidth were measured for the original diode laser and then compared to the measurements in an external cavity with and without antireflection (AR) coatings. The tuning range approximately doubled after AR coating. The modal stability was found to be better by a factor of 7 in the external cavity. The power amplification through the external cavity was as high as 50. It was also attempted to process laser diodes from material fabricated at OSU, however the resulting diodes showed a high series resistance and were not usable for this project. Additional work needs to be done in this area. The result of this work is a stable external cavity diode laser tunable over an 18 nm bandwidth which can be used as a tunable source in many applications. / Graduation date: 1995