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 18 of 18 for “"Tunable lasers"”.
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Wavelength locking and determination in tunable lasers by gain voltage measurement
In this thesis, tunable lasers under optical feedback are investigated. The influence of feedback on the spectral behaviour of the voltage at the gain section, the output power, the threshold current, the linewidth and the side mode suppression ratio are investigated. The findings complement the …
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Design and Performance Analysis of Frequency-Shift Keyed Transmitter using Rapidly Tunable Lasers
… implementation utilizing a single, fast tunable laser, allowing scalability to high values of M-ary FSK, where M represents the number of wavelengths in the symbol constellation. This work will propose and implement a design for an FSKmodulated transmitter using a modulated-grating, …
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Design and fabrication of single-mode tunable lasers for regrowth-free monolithically integrated photonic circuits
… component at the core of photonic circuits: the tunable single-mode laser, this work is a contribution to the development of components that can be fabricated without requiring any regrowth or advanced lithography. Based on multi-cavity geometries enabled by multimode interference couplers and on …
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Investigation of performance issues affecting optical circuit and packet switched WDM networks
… for fast optical switching, namely the tunable laser. Tunable lasers which can switch on the nanosecond timescale will be required in the transmitters and wavelength converters of optical packet switching networks. The switching times and frequency drifts, both of commercially available …
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Pivot-Point-Independent Mode-Hop-Free Tunable Laser with a Large Tuning Range and Narrow Linewidth
This thesis introduces a novel external cavity tunable laser which is pivot-point-independent 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, …
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Surface-emitting lasers for communications: novel metal-cavity microlasers and high-contrast-grating tunable VCSELs
… experiments of surface-emitting semiconductor lasers is presented. The design of novel micro and nanolasers using metal cavities for optical confinement is discussed. Theoretical modeling of quantum-well and quantum-dot emission properties, as well as experimental characterization of their …
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Pivot point independent, external cavity tunable laser
… in to a novel pivot point free external cavity tunable laser (PPI ECTL). Existing external cavity tunable lasers are constructed using tunable optics, such as Bragg gratings to manipulate the cavity length. These elements although functional provide instability with prolonged use as they are …
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Application of Carbon Dioxide Waveguide Lasers to Infrared Saturation Spectroscopy
The development of tunable lasers has made possible spectroscopy at a resolution previously unattainable. Although continuous-wave broadly tunable sources in the 10 pm region do not yet exist , waveguide carbon dioxide lase r s offer a useful tunability about a large number of emission lines in …
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Enhanced Modulation Dynamic Performance of Optically-Injected Widely-Tunable Semiconductor Lasers
… 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 improved …
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Investigation of wavelength tunable laser modules for use in future optically switched dense wavelength division multiplexed networks
… 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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Modification of exciton energies and dynamics for thin film optoelectronics
… light emitting diodes, visible wavelength lasers, photovoltaics, and sensors. Mediating photons and charges, excitons are responsible for electrical and optical properties in these energetically disordered media. To improve current technology and develop novel applications, a thorough …
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Exciton transport and coherence in molecular and nanostructured materials
… such as organic light emitting diodes, color tunable lasers, and low-cost photovoltaics, and hold promise as a platform for all-optical computing. The defining optical and electronic characteristic of molecular and nanostructured materials is the exciton, a bound electron hole pair. Excitons, …
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Development of Novel Compact Laser Sources for Bio-Medical Applications
… characterisation of novel semiconductor based lasers sources tunable in the broad spectral ranges that are unattainable by conventional lasers due to a lack of suitable laser gain materials.<br/><br/>Within the first part, the broad gain spectrum from quantum dot (QD) materials is seen to be an …
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Digital Holography and Optical Contouring
… speckle noise.• Fibre-based systems linked to tunable lasers, including a comprehensive analysis of the effects of: signal attenuation, noise and laser instability within such systems.• Two-source arrangements for contouring, including investigating the limitations on achievable accuracy with …
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Toward single-growth monolithically integrated electro-absorption modulated lasers
… component at the heart of photonic circuits: the tunable single-mode laser. The aim is to contribute to the development of components that can be fabricated without the need for regrowth or advanced lithography. Additionally, the study emphasises the importance of monolithic integration, …
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High Speed Wavelength Tuning of SGDBR Lasers for Optical Coherence Tomography Applications
… 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 laser light …
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Investigation of Narrowband Acousto-Optic Tunable Filters for Semiconductor Laser Tuning
Wavelength tunable sources find applications in areas of laser surgery, optical coherence tomography, material processing, and differential absorption light detection and ranging. Acousto-optic tunable filters (AOTFs) are wavelength selective devices which allow for better stability than mechanical …
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Contribución al estudio y optimización de dispositivos basados en holografía dinámica para su uso en redes ópticas pasivas multiplexadas en longitud de onda Wdm-Pon
… where the use of holographic devices, WDM tunables, takes different applications as network elements like filters, demultiplexers, wavelength routers, add/drop optical multiplexers (OADMs) and optical switching matrixes. In this work, from a theoretical study of these devices, based on …