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Articles 1441 - 1470 of 1749

Full-Text Articles in Electromagnetics and Photonics

Digital Signal Processing Techniques For Coherent Optical Communication, Gilad Goldfarb Jan 2008

Digital Signal Processing Techniques For Coherent Optical Communication, Gilad Goldfarb

Electronic Theses and Dissertations

Coherent detection with subsequent digital signal processing (DSP) is developed, analyzed theoretically and numerically and experimentally demonstrated in various fiber-optic transmission scenarios. The use of DSP in conjunction with coherent detection unleashes the benefits of coherent detection which rely on the preservation of full information of the incoming field. These benefits include high receiver sensitivity, the ability to achieve high spectral-efficiency and the use of advanced modulation formats. With the immense advancements in DSP speeds, many of the problems hindering the use of coherent detection in optical transmission systems have been eliminated. Most notably, DSP alleviates the need for hardware …

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Meshfree Approximation Methods For Free-Form Optical Surfaces With Applications To Head-Worn Displays, Ozan Cakmakci Jan 2008

Meshfree Approximation Methods For Free-Form Optical Surfaces With Applications To Head-Worn Displays, Ozan Cakmakci

Electronic Theses and Dissertations

Compact and lightweight optical designs achieving acceptable image quality, field of view, eye clearance, eyebox size, operating across the visible spectrum, are the key to the success of next generation head-worn displays. The first part of this thesis reports on the design, fabrication, and analysis of off-axis magnifier designs. The first design is catadioptric and consists of two elements. The lens utilizes a diffractive optical element and the mirror has a free-form surface described with an x-y polynomial. A comparison of color correction between doublets and single layer diffractive optical elements in an eyepiece as a function of eye clearance …

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Spatio-Spectral Sampling And Color Filter Array Design, Keigo Hirakawa, Patrick J. Wolfe Jan 2008

Spatio-Spectral Sampling And Color Filter Array Design, Keigo Hirakawa, Patrick J. Wolfe

Electrical and Computer Engineering Faculty Publications

Owing to the growing ubiquity of digital image acquisition and display, several factors must be considered when developing systems to meet future color image processing needs, including improved quality, increased throughput, and greater cost-effectiveness. In consumer still-camera and video applications, color images are typically obtained via a spatial subsampling procedure implemented as a color filter array (CFA), a physical construction whereby only a single component of the color space is measured at each pixel location. Substantial work in both industry and academia has been dedicated to post-processing this acquired raw image data as part of the so-called image processing pipeline, …

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Phase And Amplitude Modulated Ofdm For Dispersion Managed Wdm Systems, Andreas Eisele Jan 2008

Phase And Amplitude Modulated Ofdm For Dispersion Managed Wdm Systems, Andreas Eisele

Electronic Theses and Dissertations

Amplitude and phase modulated optical OFDM (Orthogonal Frequency Division Multiplexing) are analyzed in a 50GBit/s single channel and 40GBit/s 5 channel 512 subcarrier non-ideal dispersion-compensated fiber optic communication systems. PM-OFDM is investigated as an alternative to AM-OFDM to alleviate the problem associated with amplitude-modulated signals in a nonlinear medium. The inherent dispersion compensation capability in OFDM (using a cyclic prefix) allows transmission over a link whose dispersion map is not exactly known. OFDM also mitigates the effects of dispersion slope in wavelength-division multiplexed (WDM) systems. Moreover, the overall dispersion throughout the transmission link may vary due to environmental effects and …

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High Power Mode-Locked Semiconductor Lasers And Their Applications, Shinwook Lee Jan 2008

High Power Mode-Locked Semiconductor Lasers And Their Applications, Shinwook Lee

Electronic Theses and Dissertations

In this dissertation, a novel semiconductor mode-locked oscillator which is an extension of eXtreme Chirped Pulse Amplification (XCPA) is investigated. An eXtreme Chirped Pulse Oscillator (XCPO) implemented with a Theta cavity also based on a semiconductor gain is presented for generating more than 30ns frequency-swept pulses with more than 100pJ of pulse energy and 3.6ps compressed pulses directly from the oscillator. The XCPO shows the two distinct characteristics which are the scalability of the output energy and the mode-locked spectrum with respect to repetition rate. The laser cavity design allows for low repetition rate operation < 100MHz. The cavity significantly reduces nonlinear carrier dynamics, integrated self phase modulation (SPM), and fast gain recovery in a Semiconductor optical Amplifier (SOA). Secondly, a functional device, called a Grating Coupled Surface Emitting Laser (GCSEL) is investigated. For the first time, passive and hybrid mode-locking of a GCSEL is achieved by using saturable absorption in the passive section of GCSEL. To verify the present limitation of the GCSEL for passive and hybrid mode-locking, a dispersion matched cavity is explored. In addition, a Grating Coupled surface emitting Semiconductor Optical Amplifier (GCSOA) is also investigated to achieve high energy pulse. An energy extraction experiment for GCSOA using stretched pulses generated from the colliding pulse semiconductor mode-locked laser via a chirped fiber bragg grating, which exploits the XCPA advantages is also demonstrated. Finally, passive optical cavity amplification using an enhancement cavity is presented. In order to achieve the interferometric stability, the Hänsch-Couillaud Method is employed to stabilize the passive optical cavity. The astigmatism-free optical cavity employing an acousto-optic modulator (AOM) is designed and demonstrated. In the passive optical cavity, a 7.2 of amplification factor is achieved with a 50 KHz dumping rate.

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Nanostructured Engineered Materials With High Magneto-Optic Performance For Integrated Photonics Applications, Mikhail Vasiliev, Kamal Alameh, Viacheslav Kotov, Yong-Tak Lee Jan 2008

Nanostructured Engineered Materials With High Magneto-Optic Performance For Integrated Photonics Applications, Mikhail Vasiliev, Kamal Alameh, Viacheslav Kotov, Yong-Tak Lee

ECU Presentations

No abstract provided.

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Block Level Link Path Design And Multilayer Via Transition Model Assembly Using S-Parameters, Francesco De Paulis Jan 2008

Block Level Link Path Design And Multilayer Via Transition Model Assembly Using S-Parameters, Francesco De Paulis

Masters Theses

"In high-speed data communication systems the complexity of link path between transmitters and receivers present a challenge for designers to maintain an acceptable bit error rate. An approach is presented in this thesis to design the link path on a block-by-block basis. The unique advantage of this approach lies on the physics-based model of each block, which then relates performance to geometry and makes design improvement and optimization possible. A tool based on the manipulation of frequency domain data has been designed to help in the design and analysis process of fast communication systems. It accepts as inputs the frequency …

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Optical Solitons In Periodic Structures, Konstantinos Makris Jan 2008

Optical Solitons In Periodic Structures, Konstantinos Makris

Electronic Theses and Dissertations

By nature discrete solitons represent self-trapped wavepackets in nonlinear periodic structures and result from the interplay between lattice diffraction (or dispersion) and material nonlinearity. In optics, this class of self-localized states has been successfully observed in both one-and two-dimensional nonlinear waveguide arrays. In recent years such lattice structures have been implemented or induced in a variety of material systems including those with cubic (Kerr), quadratic, photorefractive, and liquid-crystal nonlinearities. In all cases the underlying periodicity or discreteness leads to new families of optical solitons that have no counterpart whatsoever in continuous systems. In the first part of this dissertation, a …

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Design And Optimization Of Nanostructured Optical Filters, Jeremiah Brown Jan 2008

Design And Optimization Of Nanostructured Optical Filters, Jeremiah Brown

Electronic Theses and Dissertations

Optical filters encompass a vast array of devices and structures for a wide variety of applications. Generally speaking, an optical filter is some structure that applies a designed amplitude and phase transform to an incident signal. Different classes of filters have vastly divergent characteristics, and one of the challenges in the optical design process is identifying the ideal filter for a given application and optimizing it to obtain a specific response. In particular, it is highly advantageous to obtain a filter that can be seamlessly integrated into an overall device package without requiring exotic fabrication steps, extremely sensitive alignments, or …

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Low Noise, High Repetition Rate Semiconductor-Based Mode-Locked Lasers For Signal Processing And Coherent Communications, Franklyn Quinlan Jan 2008

Low Noise, High Repetition Rate Semiconductor-Based Mode-Locked Lasers For Signal Processing And Coherent Communications, Franklyn Quinlan

Electronic Theses and Dissertations

This dissertation details work on high repetition rate semiconductor mode-locked lasers. The qualities of stable pulse trains and stable optical frequency content are the focus of the work performed. First, applications of such lasers are reviewed with particular attention to applications only realizable with laser performance such as presented in this dissertation. Sources of timing jitter are also reviewed, as are techniques by which the timing jitter of a 10 GHz optical pulse train may be measured. Experimental results begin with an exploration of the consequences on the timing and amplitude jitter of the phase noise of an RF source …

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Ultrashort Laser Pulse Interaction With Photo-Thermo-Refractive Glass, Leo Siiman Jan 2008

Ultrashort Laser Pulse Interaction With Photo-Thermo-Refractive Glass, Leo Siiman

Electronic Theses and Dissertations

Photo-thermo-refractive (PTR) glass is an ideal photosensitive material for recording phase volume holograms. It is a homogeneous multi-component silicate glass that demonstrates all the advantages of optical glass: thermal stability, high laser damage threshold, and a wide transparency range. Moreover the ability to record phase patterns (i.e. spatial refractive index variations) into PTR glass has resulted in the fabrication of volume holograms with diffraction efficiency greater than 99%. The conventional method of recording a hologram in PTR glass relies on exposure to continuous-wave ultraviolet laser radiation. In this dissertation the interaction between infrared ultrashort laser pulses and PTR glass is …

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Cholesteric Liquid Crystal Photonic Crystal Lasers And Photonic Devices, Ying Zhou Jan 2008

Cholesteric Liquid Crystal Photonic Crystal Lasers And Photonic Devices, Ying Zhou

Electronic Theses and Dissertations

This dissertation discusses cholesteric liquid crystals (CLCs) and polymers based photonic devices including one-dimensional (1D) photonic crystal lasers and broadband circular polarizers. CLCs showing unique self-organized chiral structures have been widely used in bistable displays, flexible displays, and reflectors. However, the photonic band gap they exhibit opens a new way for generating laser light at the photonic band edge (PBE) or inside the band gap. When doped with an emissive laser dye, cholesteric liquid crystals provide distributed feedback so that mirrorless lasing is hence possible. Due to the limited surface anchoring, the thickness of gain medium and feedback length is …

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Integrated Optical Spr (Surface Plasmon Resonance) Sensor Based On Optoelectronic Platform, Hyungseok Bang Jan 2008

Integrated Optical Spr (Surface Plasmon Resonance) Sensor Based On Optoelectronic Platform, Hyungseok Bang

Electronic Theses and Dissertations

Current major demands in SPR sensor development are system miniaturization and throughput improvement. Structuring an array of integrated optical SPR sensor heads on a semiconductor based optoelectronic platform could be a promising solution for those issues, since integrated optical waveguides have highly miniaturized dimension and the optoelectronic platform enables on-chip optical-to-electrical signal conversion. Utilizing a semiconductor based platform to achieve optoelectronic functionality poses requirements to the senor head; the sensor head needs to have reasonably small size while it should have reasonable sensitivity and fabrication tolerance. This research proposes a novel type of SPR sensor head and demonstrates a fabricated …

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Extended Focus Range High Resolution Endoscopic Optical Coherence Tomography, Kye-Sung Lee Jan 2008

Extended Focus Range High Resolution Endoscopic Optical Coherence Tomography, Kye-Sung Lee

Electronic Theses and Dissertations

Today, medical imaging is playing an important role in medicine as it provides the techniques and processes used to create images of the human body or parts thereof for clinical purposes (medical procedures seeking to reveal, diagnose or examine disease) or medical science (including the study of normal anatomy and function). Modalities are developing over time to achieve the highest possible resolution, speed of image acquisition, sensitivity, and specificity. In the past decade, advances in optics, fiber, as well as laser technology have enabled the development of noninvasive optical biomedical imaging technology that can also be applied to endoscopy to …

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A Nondestructive Technique For Determining Complex Permittivity And Permeability Of Magnetic Sheet Materials Using Two Flanged Rectangular Waveguides, Milo W. Hyde Iv, Michael J. Havrilla Nov 2007

A Nondestructive Technique For Determining Complex Permittivity And Permeability Of Magnetic Sheet Materials Using Two Flanged Rectangular Waveguides, Milo W. Hyde Iv, Michael J. Havrilla

Faculty Publications

In this paper, a nondestructive technique for determining the complex permittivity and permeability of magnetic sheet materials using two flanged rectangular waveguides is presented. The technique extends existing single probe methods by its ability to simultaneously measure reflection and transmission coefficients imperative for extracting both permittivity and permeability over all frequencies. Using Love’s Equivalence Principle, a system of coupled magnetic field integral equations (MFIEs) is formed. Evaluation of one of the two resulting spectral domain integrals via complex plane integration is discussed. The system, solved via the Method of Moments (MoM),yields theoretical values for the reflection and transmission coefficients. These …

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Examination Of Energy And Group Velocities In Positive And Negative Index Chiral Materials With And Without Dispersion, Monish Ranjan Chatterjee, Partha P. Banerjee Sep 2007

Examination Of Energy And Group Velocities In Positive And Negative Index Chiral Materials With And Without Dispersion, Monish Ranjan Chatterjee, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

Concepts of energy and group velocities, Poynting and propagation vectors are examined for both positive and negative index materials. Known definitions for these entities are explored in terms of the interplay of chirality and dispersion.

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Bipolar Cascade Vertical Cavity Surface Emitting Lasers For Rf Photonic Link Applications, William J. Siskaninetz Sep 2007

Bipolar Cascade Vertical Cavity Surface Emitting Lasers For Rf Photonic Link Applications, William J. Siskaninetz

Theses and Dissertations

The development and demonstration of bipolar cascade vertical cavity surface emitting lasers is presented. The systematic approach to designing, fabricating, and characterizing the critical tunnel junction, incorporating the tunnel junction into an edge emitting bipolar cascade laser, and finally the transition to a VCSEL structure is detailed. A novel approach prior to growing and characterizing BC VCSELs was to investigate bipolar cascade light emitting diodes which incorporate the microcavity designs and disentangles the VCSEL cavity effects from the microcavity. The best performing p-doped oxide aperture microcavity design was then used as the microcavity for 1-, 2-, and 3-stage BC …

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Nonlinear Dynamical Analysis Of Brain Electrical Activity Due To Exposure To Weak Environmentally Relevant Electromagnetic Fields, Erik Alfonso Nilsen Jul 2007

Nonlinear Dynamical Analysis Of Brain Electrical Activity Due To Exposure To Weak Environmentally Relevant Electromagnetic Fields, Erik Alfonso Nilsen

Doctoral Dissertations

The reports dealing with the effects of weak electromagnetic fields (EMFs) on brain electrical activity have been inconsistent. We suspected that the use of linear models and their associated methods accounted for some of the variability, and we explored the issue by using a novel approach to study the effects of EMFs on the electroencephalogram (EEG) from rabbits and humans. The EEG was embedded in phase space and local recurrence plots were calculated and quantified to permit comparisons between exposed and control epochs from individual subjects. Statistically significant alterations in brain activity were observed in each subject when exposed to …

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Analysis Of Beam Propagation In 90-Degree Holographic Recording And Readout Using Transfer Functions And Numerical 2-D-Laplace Inversion, Monish Ranjan Chatterjee, Partha P. Banerjee, George Nehmetallah Jun 2007

Analysis Of Beam Propagation In 90-Degree Holographic Recording And Readout Using Transfer Functions And Numerical 2-D-Laplace Inversion, Monish Ranjan Chatterjee, Partha P. Banerjee, George Nehmetallah

Electrical and Computer Engineering Faculty Publications

Recently, 2-D-Laplace analysis of recording and readout of edge-holograms was reported. Numerical Laplace inversion was examined for simple test cases. Inversion algorithms are applied to examine beam shaping and distortion in photovoltaic and photorefractive materials.

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Thermally Activated, Variable Blazed Grating For Coherent Beam Steering, Matthew T. Johnson Mar 2007

Thermally Activated, Variable Blazed Grating For Coherent Beam Steering, Matthew T. Johnson

Theses and Dissertations

The ability to perform non-mechanical optical beam steering is of critical importance in laser communication and remote sensing; it is as vital as a phased-array antenna is for RADAR. Directed energy transmission and direction-selective reception increase performance and produce tactical advantage in DoD applications. However, specific geometric features of non-mechanical beam steering devices must be designed in proportion to the wavelength of the monochromatic light to be steered. Also, the ability to handle higher energies by reducing the energy per unit requires large areas of uniform properties on the micrometer scale. These challenges have been addressed in the past using …

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Material Characterization Improvement In High Temperature Rectangle Waveguide Measurements, Eric A. Buschelman Mar 2007

Material Characterization Improvement In High Temperature Rectangle Waveguide Measurements, Eric A. Buschelman

Theses and Dissertations

This research presents a method by which electromagnetic characterization of materials in a partially filled waveguide can be accurately performed. Higher order modes are excited by the geometry, which are not accounted for in most algorithms. A correction must consider the power transmitted by higher-order modes. Modal solutions, using reference plane independence, for a single top air gap between the material sample and the waveguide wall, are also presented. Characterization is performed on samples of acrylic and rubberized magnetic radar absorbing material. Calculation of the complex permittivity and permeability of shielding material, within 10% of the true value, was achieved …

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Sub-Surface Navigation Using Very-Low Frequency Electromagnetic Waves, Alan L. Harner Mar 2007

Sub-Surface Navigation Using Very-Low Frequency Electromagnetic Waves, Alan L. Harner

Theses and Dissertations

This research proposes two schemes utilizing very-low frequency (VLF) electromagnetic waves to navigate underground. The first scheme consists of using above-ground beacon transmitters to broadcast VLF signals to an underground mobile receiver which uses methods such as triangulation and trilateration to obtain a position solution. The second scheme consists of using above-ground reference receivers along with an underground mobile receiver to form time-difference- of-arrival measurements of incoming VLF signals of opportunity, such as lightning strike emissions, to calculate a position solution. The objective of this thesis is to develop positioning algorithms and use simulations as a tool to characterize the …

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Nonlinear Time-Variant Response In An Avalanche Photodiode Array Based Laser Detection And Ranging System, Michael D. Seal Mar 2007

Nonlinear Time-Variant Response In An Avalanche Photodiode Array Based Laser Detection And Ranging System, Michael D. Seal

Theses and Dissertations

This research effort identifies and models the nonlinear time-variant behavior exhibited by an avalanche photodiode (APD) array based Laser Ranging and Detection (LADAR) system. Based on the original Linear Time-Invariant (LTI) model, the evolution of error in the LADAR signal is examined sequentially from the outgoing pulse through signal digitization. This error evolution shows that the LTI model does not contain a mechanism for causing the observed signal deviations or the failure to meet the Cramer-Rao lower bound for range accuracy. A nonlinear time-variant model is developed based on the interactions of the avalanche photodiodes in the array with the …

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Propagation Of Ultrashort Laser Pulses Through Water, Jianchao Li, Dennis R. Alexander, Haifeng Zhang, Ufuk Parali, David Doerr, John Clark Bruce Iii, Hao Wang Feb 2007

Propagation Of Ultrashort Laser Pulses Through Water, Jianchao Li, Dennis R. Alexander, Haifeng Zhang, Ufuk Parali, David Doerr, John Clark Bruce Iii, Hao Wang

Department of Electrical and Computer Engineering: Faculty Publications

In this paper, propagation of ultrashort pulses through a long 3.5 meter water channel was studied. Of particular interest was the attenuation of the beam at various lengths along the variable path length and to find an explanation of why the attenuation deviates from typical Beer Lambert law around 3 meters for ultrashort laser pulse transmission. Laser pulses of 10 fs at 75 MHz, 100 fs at 80 MHz and 300 fs at 1 KHz were employed to investigate the effects of pulse duration, spectrum and repetition rate on the attenuation after propagating through water up to 3 meters. Stretched …

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Study Of Soliton Stabilization In D+1 Dimensions Using Novel Analytical And Numerical Techniques, George Nehmetallah, Partha P. Banerjee Jan 2007

Study Of Soliton Stabilization In D+1 Dimensions Using Novel Analytical And Numerical Techniques, George Nehmetallah, Partha P. Banerjee

Electrical and Computer Engineering Faculty Publications

In this Chapter, we provide a brief review of the underlying nonlinear Schrödinger and associated equations that model spatio-temporal propagation in one and higher dimensions in a nonlinear dispersive environment. Particular attention is given to fast adaptive numerical techniques to solve such equations, and in the presence of dispersion and nonlinearity management, saturating nonlinearity and nonparaxiality. A unique variational approach is also outlined which helps in determining the ranges of nonlinearity and dispersion parameters to ensure stable solutions of the nonlinear equations. The propagation of 3+1 dimensional spatio-temporal pulses, or optical bullets is also modeled using a fast adaptive split-step …

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Atmospheric Turbulence Compensation Of Point Source Images Using Asynchronous Stochastic Parallel Gradient Descent Technique On Amos 3.6 M Telescope, Mikhail Vorontsov, Jim F. Riker, Gary W. Carhart, Venkata S. Rao Gudimetla, Leonid A. Beresnev, Thomas Weyrauch Jan 2007

Atmospheric Turbulence Compensation Of Point Source Images Using Asynchronous Stochastic Parallel Gradient Descent Technique On Amos 3.6 M Telescope, Mikhail Vorontsov, Jim F. Riker, Gary W. Carhart, Venkata S. Rao Gudimetla, Leonid A. Beresnev, Thomas Weyrauch

Electrical and Computer Engineering Faculty Publications

The Stochastic Parallel Gradient Descent Technique-based Adaptive Optics (SPGD-AO) system described in this presentation does not use a conventional wavefront sensor. It uses a metric signal collected by a single pixel detector placed behind a pinhole in the image plane to drive three deformable mirrors (DMs). The system is designed to compensate the image for turbulence effects. The theory behind this method is described in detail in [1]. However this technique, while widely simulated and tested in the laboratory, was not yet verified in astronomical field site experiments. During the month of May 2007, a series of experiments with SPGD-AO …

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Adaptive Optics Performance Over Long Horizontal Paths: Aperture Effects In Multi-Conjugate Adaptive Optical Systems, Miao Yu, Mikhail Vorontsov, Svetlana Lachinova, Jim F. Riker, Venkata S. Rao Gudimetla Jan 2007

Adaptive Optics Performance Over Long Horizontal Paths: Aperture Effects In Multi-Conjugate Adaptive Optical Systems, Miao Yu, Mikhail Vorontsov, Svetlana Lachinova, Jim F. Riker, Venkata S. Rao Gudimetla

Electrical and Computer Engineering Faculty Publications

We analyze various scenarios of the aperture effects in adaptive optical receiver-type systems when inhomogeneities of the wave propagation medium are distributed over long horizontal propagation path, or localized in a few thin layers remotely located from the receiver telescope pupil. Phase aberration compensation is performed using closed-loop control architectures based on phase conjugation and decoupled stochastic parallel gradient descent (DSPGD) control algorithms. Both receiver system aperture diffraction effects and the impact of wave-front corrector position on phase aberration compensation efficiency are analyzed for adaptive systems with single or multiple wave-front correctors.

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Polarisation Dependence Of Bend Loss For A Standard Singlemode Fiber, Qian Wang, Ginu Rajan, Pengfei Wang, Gerald Farrell Jan 2007

Polarisation Dependence Of Bend Loss For A Standard Singlemode Fiber, Qian Wang, Ginu Rajan, Pengfei Wang, Gerald Farrell

Articles

Polarization dependence of bend loss caused by the polymer coating layer for a standard singlemode fiber (SMF28) is investigated theoretically and experimentally. Bend loss for SMF28 for both the TE and TM mode is calculated separately. Normalized polarization dependent loss is proposed for the characterization of the polarization sensitivity of bend loss for different bend radii. Corresponding experimental tests are presented, which agree with the theoretical results. Both the theoretical and experimental results show that the polymer coating layer has a significant influence on the polarization dependence of bend loss.

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Infrared Antenna-Coupled Phased-Array, Christopher Middlebrook Jan 2007

Infrared Antenna-Coupled Phased-Array, Christopher Middlebrook

Electronic Theses and Dissertations

Phased-array antennas are commonplace in the radiofrequency portion of the electromagnetic spectrum. Exploitation of phasing effects between multiple antennas facilitates a wide range of applications, including synthetic-aperture radar, beam forming, and beam scanning. For the first time, the phased addition of multiple dipole antennas is demonstrated in the infrared, at a wavelength of 10.6 micrometers. Coplanar strip lines are used to interconnect the antennas, preserving the phase of the individual contributions. Several different proof-of-concept experiments are performed, using planar antennas fabricated with direct-write electron-beam lithography. Infrared-frequency currents from two dipole antennas are summed together at a common feedpoint and dissipated …

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High-Speed Modelocked Semiconductor Lasers And Applications In Coherent Photonic Systems, Wangkuen Lee Jan 2007

High-Speed Modelocked Semiconductor Lasers And Applications In Coherent Photonic Systems, Wangkuen Lee

Electronic Theses and Dissertations

1.55-µm high-speed modelocked semiconductor lasers are theoretically and experimentally studied for various coherent photonic system applications. The modelocked semiconductor lasers (MSLs) are designed with high-speed (>5 GHz) external cavity configurations utilizing monolithic two-section curved semiconductor optical amplifiers. By exploiting the saturable absorber section of the monolithic device, passive or hybrid mode-locking techniques are used to generate short optical pulses with broadband optical frequency combs. Laser frequency stability is improved by applying the Pound-Drever-Hall (PDH) frequency stabilization technique to the MSLs. The improved laser performance after the frequency stabilization (a frequency drifting of less than 350 MHz), is extensively studied …

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