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 “"Fibre laser"”.
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Cladding-pumped Raman fibre laser sources
… this thesis, I investigate cladding-pumped Raman fibre lasers and amplifiers. Such devices, offering a novel way to generate Raman gain, combine the advantages of the hugely successful cladding-pumped rare-earth doped fibre lasers with those of stimulated Raman scattering. They not only inherit …
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Distributed feedback fibre laser strain and temperature sensors
… types of polarimetric distributed feedback (DFB) fibre laser sensors for simultaneous strain and temperature measurements. These fibre Bragg grating (FBG) based sensors offer strain and temperature measurement accuracies of ±0.3 - ±15 µ.epsilon and ±0.04 - ±0.2°C which are suitable for many …
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High-power diode-pumped ytterbium-doped fibre-laser
… I have done on double cladding ytterbium-doped fibre lasers. The two main subjects developed were the study of an efficient compact-launching system, and the operation of the double cladding compact fibre as a continuous-wave laser and a Q-switched laser. During this work, highly efficient side …
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Dynamics of a Q-switched all-fibre laser
… and numerical investigations of self-pulsing in fibre lasers with a gain section and an absorber section via a mechanism known as Q-switching. In the context of an all-fibre laser, experimentally, we consider a Fabry-Perot resonator with sectional gain and absorption and their interaction while, …
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Two micron Tm doped ZBLAN double clad fibre laser.
Tm:ZBLAN fibre lasers have potential applications in many research areas, such as eye safe range detection, medical science and materials processing. In this thesis we investigate improving the laser performance of a thulium doped fluoride fibre (specifically ZBLAN) to generate laser output with …
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Advanced high-power pulsed fibre laser systems and their applications
… studies towards power scaling of ultrashort fibre-based sources designed for applications including high average power femtosecond pulse generation and nonlinear frequency conversion. While the power produced by rare-earth doped fibre lasers operating in continuous-wave has dramatically …
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Thulium-doped fibre laser in the 2 μm wavelength region for gas sensing
… Thulium is widely studied for generating lasers at wavelength near 2 μm. For decades, tuneable continuous wave narrow line-width sources in this wavelength region have been proved to be very useful as spectroscopic tools for trace gas detection. Semiconductor lasers are often not readily …
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Laser micro-processing of silicon using nanosecond pulse shaped fibre laser at 1 μm wavelength
… Diode Pumped Solid State (DPSS) Ultraviolet (UV) laser. Recent advances in laser source technology have produced fibre lasers with Master Oscillator Power Amplifier (MOPA) architectures that offer high repetition rates, high operational efficiencies, and pulse modulation controls exceeding those …
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Development of bismuth doped silica fibres for high power sources & long wavelength generation from ytterbium doped fibre lasers
… of bismuth (Bi) doped silica optical fibre has been investigated. Three different fibre fabrication techniques were applied to study the possible influence on Bi-luminescence: modified chemical vapour deposition (MCVD) and the solution doping technique, MCVD chemical-in-crucible …
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High-power fibre lasers
… rare-earth (Yb3+, Er3+/Yb3+)-doped fibre lasers. Some of the main capabilities of fibre lasers such as: High brightness and thermal properties were exploited for the development of a variety of continuous wave (CW) and Q-switched devices, whose characteristics also includes …
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Fibre-based devices for next generation photonics communication systems
… and distribution of radio frequency signals over fibres, and the fibre optic signal processing of optical and radio frequency signals, have been the subjects for study in this thesis. Based on the intrinsic properties of single-mode optical fibres, and in conjunction with the concepts of optical …
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Novel power scaling architectures for fibre and solid-state sources
… scaling the output power of rare-earth ion doped fibre lasers and amplifiers, fibre amplified spontaneous emission sources, and solid state laser oscillators. Scaling output power from laser sources has been a topic of interest ever since the first laser was demonstrated. The development of new …
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High-power cladding-pumped Raman and erbium-ytterbium doped fibre sources
Raman fibres and rare-earth doped silica fibres have been investigated for many years as gain media for the amplification of optical signals in telecommunications thanks to their broad gain bandwidth. They are now widely used for that application. It is only recently that power scaling of fibre …
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Environmentally stable, near-infrared, mode-locked fibre lasers for industrial applications
Mode-locked laser systems that show robust operation in the presence of environmental instabilities are desirable for numerous applications in the defence sector and beyond. In this thesis I present the development of two such systems based on fibre-laser architecture and developed for applications …
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Bragg grating filters for optical networks
This thesis focuses on the exploitation of fibre Bragg gratings in optical communication networks. New designs, as well as procedures for dynamically altering grating characteristics are proposed for several important functions. We begin with designing gratings for flattening the gain profile of an …
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Advanced waveguides for high power optical fibre sources
… Nd<sup>3+</sup>- and Yb<sup>3+</sup>-doped fibre lasers. Cladding-pumped high-power fibre lasers based on these novel waveguide designs and operating at desired unconventional wavelengths were investigated through numerical simulations and fibre laser experiments.<br/>Rare earth doped fibres …
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Passive and active Bragg gratings for optical networks
This thesis investigates fibre Bragg grating (FBG) devices. Specifically, it consists of the developments and applications of two groups of devices: the optical phase en/decoders and the tunable fibre Bragg gratings based on an S-bending technique. The advantage of an S-bending tuning FBG is that …
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Laser induced incandescence imaging for the investigation of soot formation in laminar flames
This work has been aimed at applying laser induced incandescence imaging for the measurement of soot concentration within a variety of novel flame sources and setups. Laser induced incandescence (LII) is an optical technique used in laser diagnostics to measure soot volume fraction and estimate …
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Environmentally Stable Mode-locked Fibre Lasers in the Near-Infrared
… a study of environmentally stable, mode-locked fibre laser systems operating in the near-infrared. Such lasers can be characterised as all-fibre systems, producing pulses of picosecond or femtosecond duration. The thesis covers a range of regimes of operation, across three wavelength bands that …
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Development of non-linear waveguide devices for optical signal processing
… to crystals, becomes feasible in glass fibres and waveguides which are widely spread media in photonics thanks to their excellent optical properties and mature manufacturing technology. Poled silica glass, despite showing about 10 times lower second-order nonlinearity than nonlinear …
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