Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 30 for “"Wavelength tuning"”.
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High Speed Wavelength Tuning of SGDBR Lasers for Optical Coherence Tomography Applications
… Grated Distributed Bragg Reflector (SGDBR) wavelength tunable lasers for swept-wavelength Optical Coherence Tomography (OCT) is explored. OCT is a method of measuring reflectivity versus distance into samples under test with a focused infrared light source. Swept wavelength OCT requires a …
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Resonant Wavelength Tuning and CMOS Circuits for Silicon Photonic Transmitters with Microring Modulators
… (MZMs). MRMs are particularly advantageous for wavelength-division multiplexing (WDM) transceivers, where their wavelength-selective nature enables dense spectral utilization. However, their widespread adoption is hindered by electro-optic (EO) nonlinearity and sensitivity to process and thermal …
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Development of Novel Compact Laser Sources for Bio-Medical Applications
… a broad tunability for both repetition rate and wavelength which could be achieved. Similarly quantum-dot semiconductor optical amplifiers (QD-SOA) are suitable for the broadband pulse power amplification.<br/><br/>Furthermore, master oscillator power amplifier (MOPA) picosecond optical pulse …
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Theory and Modelling of Wavelength Tunable Laser Transmitters With Enhanced Tuning Range and Their Modulation Performance
… discontinuous, continuous and quasicontinuous wavelength tuning and direct Intensity Modulation (IM) (small-signal analysis). Two software simulation tools were used to model the TLDs and investigate their operation, Crosslight PICS3D and VPI (Virtual Photonics Incorporated). Two different …
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Enhanced Modulation Dynamic Performance of Optically-Injected Widely-Tunable Semiconductor Lasers
… modulation characteristics of semiconductor wide-wavelength tunable laser diodes (TLDs). The two major goals were to investigate how modulation properties of a TLD depend on the wavelength tuning, and how the modulation performance of a TLD can be enhanced in terms of the achievable speed and …
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Optically tunable external cavity ring laser
… layer of an azobenzene solution as the wavelength-selective element. Wavelength tuning is realized through optical illumination of a thin layer of azobenzene, which causes a refractive index change of the azobenzene molecules produced by photon-induced, cis→trans isomerization, thus …
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Discrete frequency mid-infrared spectroscopic imaging using quantum cascade lasers
… biological samples where the mid to far-infrared wavelength range corresponds with the vibrational modes of functional groups in many organic molecules. In recent years, the technology enabling discrete frequency infrared (DFIR) spectroscopic microscopy has undergone many substantive changes due …
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Triggered infrared emitter displays for individual identify friend-or-foe (IIFF) and vehicular mounted indentify friend-or-foe (VMIFF) devices.
… Quantum dots down conversion could be used for wavelength tuning of the polymer organic light emitting material.
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Wavelength swept spectrally encoded confocal microscopy for biological and clinical applications
… was achieved through the development of a novel wavelength swept laser which simultaneously provided high output power (> 10mrW), narrow linewidth (10GHz), broad wavelength tuning (80 nm centered at 1310 nm) and fast repetition rates (up to 16,000 Hz), while being compact and environmentally …
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Hybrid laser with CMOS photonics
… allowing for lasing at virtually arbitrary wavelengths, the possibility of multiwavelength operation with a shared gain medium, elimination of closed-loop control of wavelength tuning, ability to control laser output and wavelength on-chip, and the potential for wavelength modulation using …
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Optically Pumped Type-II Mid-Infrared Tunable Distributed Feedback Lasers
… waveguide epi-structure of the laser de- vice. Wavelength tuning is achieved by translationally projecting pump stripe at di\ufb00erent positions of this chirped grating on the laser device, thus di\ufb00erent grat- ing periods along the pump stripe at di\ufb00erent pump positions select …
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Solution-processable, mechanically-flexible lasers
… Other important outcomes include mechanical wavelength tuning of lasers, record performance for colloidal quantum dot lasers optically-pumped in the nanosecond regime and the demonstration of a red/green/blue laser. The capability for sensing applications of some reported formats of lasers …
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Swept-Frequency Sampled Grating Distributed Bragg Reflector Lasers Optimized for Optical Coherence Tomography Applications
… high repetition rate and wide spectral width wavelength tunable sources at a low cost. The sampled grating distributed Bragg reflector (SG-DBR) laser provides wide wavelength tuning range while exhibiting a wavelength switching speed that is among the fastest currently available. The SG-DBR …
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Micro-opto-mechanical switching and tuning for integrated optical systems
… for integrated optical circuits would provide wavelength-selective switching. Wavelength- selective behavior is an important characteristic for devices intended for networking applications as wavelength division multiplexing (WDM) of optical signals has become the accepted standard. A major …
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Wavelength locking and determination in tunable lasers by gain voltage measurement
… existing theory under the aspect of continuous wavelength tuning and the influence of a reflection with a fixed distance to the laser cavity. Furthermore, a more comprehensive theory of the internal and mirror losses is developed to explain the variations in the voltage curves. The theory shows …
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Advancing Photoacoustic Imaging Technology with Compact Source, Fluorescence Co-registration, Spectral Encoding, Matrix Detection and FRET
… in single blood vessels. Spectral (multi-wavelength) photoacoustic imaging must possess high wavelength-switching speed when applied in dynamic functional imaging. We implemented a digital-mirror-device (DMD)-based spectral-encoding photoacoustic imaging system. As a wavelength …
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Fiber Laser Based Nonlinear Spectroscopy
… single fiber laser, with electrically controlled wavelength-tuning and spectral resolution enhanced by a pulse shaping technique, will efficiently produce optical excitation that allows quantitative measurement of important nonlinear optical properties of materials. The work represented here …
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Pivot-Point-Independent Mode-Hop-Free Tunable Laser with a Large Tuning Range and Narrow Linewidth
… with a large mode-hop-free tuning range and fast tuning speed. The research focuses on the laser cavity design that achieves mode-hop-free tuning. <br/><br/>Among the diverse categories of tunable lasers, external cavity tunable lasers demonstrate superior performance, …
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Investigation of wavelength tunable laser modules for use in future optically switched dense wavelength division multiplexed networks
This thesis investigates the use of fast wavelength tunable laser modules in future optically switched dense wavelength division multiplexed networks (DWDM). The worldwide demand for increasingly greater broadband access has thus far been satisfied by the use of DWDM networks, enabled by the …
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Adaptation of VT-Dbr Lasers for LIDAR
… due to their continuous and nearly 40 nm wavelength tuning range in a single longitudinal mode. Fast sweeps allow for real time imaging with micrometer resolution at a distance of a few centimeters. While this laser has proven quite useful as a medical imaging tool via OCT, it has yet to …
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