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1
Gloag, Andrew John. "Tunable erbium doped fibre lasers." Thesis, University of Strathclyde, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249838.
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Graydon, Oliver. "Advanced erbium-doped fibre devices." Thesis, University of Southampton, 1996. https://eprints.soton.ac.uk/396447/.
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Erbium-doped fibre devices, such as lasers and amplifiers, are important components in optical communication systems at 1.5µm. In this thesis four advanced erbium-doped fibre devices to help meet the needs of future systems are described. The first device, an optical limiting amplifier, provides a constant output power for a wide range of input powers. This functionality is required in long-haul amplified links and networks to protect against signal power fade. The other three devices are constructed from erbium-doped twincore fibre which exhibits inhomogeneous saturation characteristics at room temperature, conventional erbium-doped fibre only exhibits this property at cryogenic temperatures. The twincore fibre is demonstrated to particularly suit multi-channel amplification and generation and is used to construct a multiple wavelength laser and channel equalising amplifier. Both of these devices are needed for future wavelength division multiplexing (WDM) systems and are difficult to construct from conventional erbium-doped fibre because of its homogeneous saturation characteristics. Finally, a tracking bandpass filter is constructed from a single piece of unpumped twincore fibre. The filter automatically tunes to the wavelength of the optical signal and has potential for guiding solitons in ultralong communication links.
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Cowle, Gregory John. "Narrow-linewidth erbium-doped fibre lasers." Thesis, University of Southampton, 1991. https://eprints.soton.ac.uk/399361/.
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This thesis describes research towards narrow-linewidth and single-longitudinal-mode erbium-doped fibre lasers operating on the 1.55µm region. The work is concerned with the physics and technology of narrow-linewidth fibre lasers. Factors which affect the spectral width and number of modes oscillating in an erbium-doped fibre laser are described, with particular reference to spatial holeburning, the primary cause of multi-mode oscillation. Novel resonator configurations for narrow-linewidth operation are described, in both standing-wave and travelling-wave arrangements, with linewidths as narrow as 10Hz being achieved. The development of narrow-bandwidth distributed Bragg reflectors is discussed. Resonator configurations discussed include short fibre lasers with narrow bandwidth reflectors, polarimetric coupled-cavity fibre lasers, travelling-wave fibre ring lasers and travelling-wave fibre loop lasers. Travelling-wave operation is demonstrated to be a powerful technique for realising single-frequency fibre laser operation. Linewidths as narrow as 10kHz are demonstrated in long fibre laser resonators. The potential for high efficiency and broad tuning ranges are illustrated. The statistics of phase noise in erbium-doped fibre amplifiers are characterised, by measurements of spectral broadening of a signal passing through the amplifier. The process of spectral broadening is modelled using a rotating vector approach. The implications for amplification of narrow bandwidth signals are discussed.
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McMillan, Duncan. "Spectrum engineering in erbium doped fibre devices." Thesis, University of Strathclyde, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273815.
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Morkel, Paul Roos. "Active neodymium and erbium doped fibre devices." Thesis, University of Southampton, 1990. https://eprints.soton.ac.uk/399485/.
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In this thesis a number of rare-earth-doped fibre devices are described including fluorescent and superfluorescent sources as well as several laser configurations. The laser configurations are all-fibre and include a neodymium-doped ring laser and recirculating delay line, a novel tunable neodymium-doped fibre laser and a single-frequency travelling-wave erbium-doped ring laser. The latter device has been the first description of a travelling-wave fibre laser device. Theory describing general fibre amplifier and laser devices is incorporated. A novel lumped element approach to fibre laser theory has been given applicable to 3 and 4-level laser devices which, under certain conditions, allows single pass gain of a fibre device to be described simply by the absorbed pump power. Numerical modelling of the erbium-doped fibre amplifier has been described which allows for analysis of a general device showing pump excited-state absorption. Results from the analysis have shown a difference in gain characteristics between co-propagating and counter-propagating signal/pump schemes when subject to pump excited-state absorption. In addition, the effect of pump direction on the noise figure is characterised in both small and large signal operating regimes. Characterisation of neodymium-doped fibres has shown a number of effects which will affect their use in amplifier and oscillator configurations. These include observation of sensitivity of the fluorescence characteristics to pump wavelength, observation of excited state absorption and polarisation of fluorescence. Additionally, the spectral gain-saturation characteristics have been investigated.
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Ye, Chen Chun. "Spectroscopy of erbium-doped fibre amplifiers and lasers." Thesis, University of Southampton, 1995. https://eprints.soton.ac.uk/399077/.
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This thesis describes work done in investigating Er3+-doped fibre amplifiers and lasers, with emphasis on the spectral properties and diagnosis of ion-ion interaction processes in the glasses and fibres. Ion-pair upconversion and uniform upconversion in Er3+-doped silicate fibres have been directly and separately observed for the first time, by examining upconversion fluorescence. An upper limit to the Er3+ ion-pair lifetime of a few microseconds has been determined. Different effects of the two upconversion mechanisms on the 1.54µm fluorescence have been examined. Ion-pair upconversion in an Al/Ge/Si or an Al/Si host increases far less with increasing Er3+ concentration than in a Ge/Si host, while there is no significant difference in uniform upconversion between them for a given Er3+ concentration. Uniform upconversion constants for various fibres are determined through measuring the maximum decay rate of the 1.54µm fluorescence. The 1.7µm ESA spectrum from the 4H13/2 level has been measured for Er3+-doped silicate fibre and ion-exchanged silicate planar waveguides, and the uniform upconversion constants are estimated. The existence of dual excited-state energy transfer (DESET) in Er3+/Yb3+- doped phospho-silicate fibres has been inferred from measurement of the ESA spectrum around 1.1µm. The absence of ESA at pump wavelength 1.064µm has also been confirmed. The DESET process has been examined for the first time by measurements of 1.064µm pump throughput characteristics of the fibre. Short Er3+/Yb3+ amplifiers pumped at around 970nm have been numerically characterized. The advantage of codoping of Yb3+ is shown to be the potential for higher gain at shorter amplifier length. By examining Er3+-doped fibre preforms with differing co-dopant ions, Ta5+- codoped fibre is shown to be competitive with Al3+-codoped fibre for Er3+-doped fibre devices. A SiGeTaEr fibre laser has been demonstrated for the first time. Spectral properties of Er3+-doped Ga2S3:La2S3 have been studied. Emission and absorption spectra, including for the first time the 2.7µm emission, are measured. Radiative and non-radiative transition rates are calculated and compared with the measured lifetimes. Characteristics of ion-ion energy transfer processes in the glass are discussed. A numerical model has been developed to predict the Performance of Er3+:Ga:La:S fibre devices, including short amplifiers operating at 1.54µm, 980nm upconversion lasers.
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O, Cochlain Ciaran R. "Tunable erbium doped fibre lasers for lightwave communication systems." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283935.
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Lim, Ee Leong. "Pump conditioning and optimisation for erbium doped fibre applications." Thesis, University of Southampton, 2012. https://eprints.soton.ac.uk/350230/.
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This thesis presents my investigation into in-band pumped erbium doped fibre amplifiers (EDFAs) and their performance under high power continuous wave (cw) operation and high energy low repetition rate pulsed operation. In addition, Q-switched erbium doped fibre lasers were investigated and used as the seed laser for a high energy low repetition rate EDFA system. Furthermore, the power scaling of all-fibre frequency doubled fibre lasers based on periodically poled silica fibre (PPSF) was also investigated. In Q-switched fibre lasers, the multiple-peak phenomenon (MPP) is an undesirable effect in which the Q-switched pulse develops sub-structure or even breaks into multiple sub pulses. I demonstrated that the MPP can be eliminated by increasing the acousto-optic modulator rise time. An experimentally validated numerical model was also used to explain the origin of MPP. Next, I showed that the interplay between MPP and modulation instability (MI) changes the detail of the spectral evolution of the Q-switched pulses. The in-band EDFAs were investigated using 1535 nm pump fibre lasers. For cw operation, a highly efficient (~ 80%), high power (18.45 W) in-band, core pumped erbium/ytterbium co-doped fibre laser was demonstrated. Using a fitted simulation model, I showed that the significantly sub-quantum limit conversion efficiency of in-band pumped EDFAs observed experimentally can be explained by concentration quenching. I then numerically studied and experimentally validated the optimum pumping configuration for power scaling of in-band, cladding pumped EDFAs. My simulation results indicate that a ~ 77% power conversion efficiency with high output power should be possible through cladding pumping of current commercially available pure erbium doped active fibres providing the loss experienced by the cladding guided 1535 nm pump due to the coating absorption can be reduced to an acceptable level by better coating material choice. The power conversion efficiency has the potential to exceed 90% if concentration quenching of erbium ions can be reduced via improvements in fibre design and fabrication. For low repetition rate pulsed operation, I demonstrated and compared high-energy, in-band pumped EDFAs operating at 1562.5 nm under both a core pumping scheme (CRS) and a cladding pumping scheme (CLS). The CRS/CLS sources generated smooth, single-peak pulses with maximum pulse energies of ~1.53/1.50 mJ, and corresponding pulse widths of ~176/182 ns respectively, with an M^2 of ~1.6 in both cases. However, the conversion efficiency for the CLS was >1.5 times higher than the equivalent CRS variant operating at the same pulse energy due to the lower pump intensity in the CLS that mitigates the detrimental effects of concentration quenching. With a longer fibre length in a CLS implementation a pulse energy of ~2.6 mJ was demonstrated with a corresponding M^2 of ~4.2. Using numerical simulations I explained that the saturation of pulse energy observed in my experiments was due to saturation of the pump absorption. For the frequency doubling work, the fundamental pump source of the PPSF was a master oscillator power amplifier seeded with a tuneable external cavity laser. During the high power operation, the heat deposition along the PPSF shifted the optimal quasi-phase matched wavelength to a longer wavelength. This shift must be compensated to achieve optimal performance of the PPSF under test and was achieved in my experiment by tuning the central wavelength of the pump source. At the end of the high power experiment, the PPSF samples degraded to ~40% of their pristine PPSF normalised efficiencies. The glass property of the PPSF had also been changed by the high power exposure. A high power all-fibre frequency doubled laser was demonstrated with 1.13 W of second harmonic average power with ~27% internal conversion efficiency.
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Cheney, Glenn P. (Glenn Peter) Carleton University Dissertation Engineering Electrical. "All-optical gain switching of erbium-doped fibre amplifiers." Ottawa, 1992.
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Forster, Richard John. "Development and applications of single frequency erbium doped fibre lasers." Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248516.
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Males, Mladen. "Suppression of transient gain excursions in an erbium-doped fibre amplifier." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2007. http://theses.library.uwa.edu.au/adt-WU2007.0157.
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This thesis reports original work on suppression of transient gain excursions in an erbium-doped fibre amplifier (EDFA). The work presented in this thesis is a detailed investigation of four closed-loop systems that control the EDFA gain dynamically. The performance of the four closed-loop systems is evaluated by analytical work, supplemented by computer simulations and insystem measurements performed on a hardware EDFA. In addition, a stability analysis of the four closed-loop systems is presented. In the stability analysis presented in this thesis, nonlinear nature of the four closed-loop systems is taken into consideration. In the stability analysis, in addition to proving that the four closed-loop systems considered are stable, it is proven that for any practical values of the EDFA gain at the initial time of observation, the EDFA gain is restored to the desired value in steady state. These outcomes of the stability analysis are supported by simulation results and experimental results. Errors in system modelling, change in the operating point of the nonlinear closed-loop system, and measurement noise are important aspects of practical implementations of systems that control the EDFA gain dynamically. A detailed analysis of the effects these practical aspects have on the performance of the four closed-loop systems considered is presented. The analysis is validated using computer simulations and experimental measurements. In most of the work reported in the literature on controlling the EDFA gain, controllers that include feedforward and/or feedback components are employed. In the traditional approaches to combining the feedforward and the feedback components, large transient excursions of the EDFA gain can still occur due to errors in the control provided by the feedforward component. In this thesis, a novel approach to combining the feedforward and the feedback components of the controller is presented. Based on the analytical work, the computer simulations and the experimental work presented in this thesis, the novel approach provides a significant reduction in the excursions of the EDFA gain in the transient period.
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Codemard, Christophe André. "High-power cladding-pumped Raman and erbium-ytterbium doped fibre sources." Thesis, University of Southampton, 2007. https://eprints.soton.ac.uk/47776/.
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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 laser sources has taken place with the development of double-clad fibres and highpower laser diode pump sources. Cladding-pumped fibre lasers are now a rapidly expanding and emerging technology with a wide range of applications, where high-power and high-brightness laser sources are required. Nevertheless, so far, most high-power lasers have been based on highly efficient ytterbium-doped fibre, while progress to power-scale other rare-earth doped fibres and fibre Raman laser has been much more modest. This thesis can be divided into two main themes. The first concerns the power-scaling and study of erbium-ytterbium doped fibre laser sources for optical amplification or as laser sources. The second theme concerns the development and study of high-power Raman fibre lasers and amplifiers based on the novel concept of a cladding-pumped Raman fibre. The themes are jointed in that the cladding-pumped Er:Yb doped lasers, developed in the first theme, are used as pump sources in this second part for the Raman devices. They are also jointed in that they both concern power-scaling of “eye-safe” sources at around 1.6 mm. Firstly, in collaboration with co-workers, high-power, large core, erbium-ytterbium doped fibre laser sources are developed. Output powers in excess of 70 W are obtained. Good beam quality output is achieved thanks to a tapered fibre section. The taper is compatible with standard single-mode fibre which enabled the realization of tuneable fibre lasers free from bulk external grating. The laser’s tuning characteristics are investigated in the C- and L-band range. Subsequently, a master-oscillator power-amplifier (MOPA) based on large core Er:Yb doped fibres is developed for the generation of high-energy pulses. The details of the MOPA are studied and presented. With careful design considerations, pulses free from non-linear effects, with energy up to 1 mJ and peak powers up to 6.6 kW, with narrow spectral linewidth, are obtained at 1535 nm. Secondly, using a double-clad fibre, consisting of raised index, germanium doped, core and inner cladding, with a pure silica outer cladding, a high-power CW single mode Raman fibre laser, pumped by a multi-mode erbium-ytterbium doped fibre laser, is demonstrated for the first time. The laser slope efficiency is 67% and the output power is in excess of 10 W. An experimental and theoretical study of the laser is performed. Then, the pulse amplification in a cladding-pumped Raman fibre is studied in a single pass amplifier configuration. The effects on the laser performance of the pump and Stokes seed powers, fibre length and four-wave mixing are presented. The Stokes’s small-signal gain can be as high as 50 dB. Using this configuration, 700 ns long pulses are amplified up to 10 mJ which shows that, potentially, optical pulses could be amplified to much higher energy. Finally, these results together, let predict that, soon, cladding-pumped Raman fibre could be used as direct brightness converter.
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Males, Mladen. "Suppression of transient gain excursions in an erbium-doped fibre amplifier /." Connect to this title, 2006. http://theses.library.uwa.edu.au/adt-WU2007.0157.
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Dimopoulos, C. "Study of dynamic phenomena in WDM optical fibre links and networks based on EDFAs." Thesis, University of Essex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.327071.
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Wijaya, Shierly. "Fixed-point realisation of erbium doped fibre amplifer control algorithms on FPGA." University of Western Australia. School of Electrical, Electronic and Computer Engineering, 2009. http://theses.library.uwa.edu.au/adt-WU2009.0132.
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The realisation of signal processing algorithms in fixed-point offers substantial performance advantages over floating-point realisations. However, it is widely acknowledged that the task of realising algorithms in fixed-point is a challenging one with limited tool support. This thesis examines various aspects related to the translation of algorithms, given in infinite precision or floating-point, into fixed-point. In particular, this thesis reports on the implementation of a given algorithm, an EDFA (Erbium-Doped Fibre Amplifier) control algorithm, on a FPGA (Field Programmable Gate Array) using fixed-point arithmetic. An analytical approach is proposed that allows the automated realisation of algorithms in fixedpoint. The technique provides fixed-point parameters for a given floating-point model that satisfies a precision constraint imposed on the primary output of the algorithm to be realised. The development of a simulation framework based on this analysis allows fixed-point designs to be generated in a shorter time frame. Albeit being limited to digital algorithms that can be represented as a data flow graph (DFG), the approach developed in the thesis allows for a speed up in the design and development cycle, reduces the possibility of error and eases the overall effort involved in the process. It is shown in this thesis that a fixed-point realisation of an EDFA control algorithm using this technique produces results that satisfy the given constraints.
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Perry, Ian Richard. "Investigations into ytterbium, ytterbium-erbium and thulium-doped silica-based fibre lasers." Thesis, University of Southampton, 1991. https://eprints.soton.ac.uk/427927/.
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Kang, Qiongyue. "Modelling of Multimode Erbium-Doped Fibre Amplifiers for mode-division multiplexed transmission systems." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/386212/.
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This PhD thesis, undertaken within the framework of MODEGAP, covers the design and optimization of high-performance in-line Multimode Erbium-Doped Fiber Amplifiers (MM-EDFAs) or Few-mode (FM) EDFA for next-generation SDM transmission systems based on Mode-Division Multiplexing (MDM). In the MM-EDFAs, minimizing the differential modal gain (DMG) is of paramount importance to prevent system outage. By using an experimentally validated commercial amplifier simulator, I proposed a 2-mode-group EDF design incorporating ring doping that allows accurate modal gain control amongst the two-mode groups using a simple and much more practical LP01 pump mode. Subsequently a 2-mode-group ring-doped EDF according to my design was fabricated in-house and a portable 2-mode-group EDFA with low DMG built and tested, confirming my predictions. My 2-mode-group EDFA design lay at the heart of several successful 2-mode-group fiber based transmission experiments, as listed in this thesis. To investigate the vector modes effects in FM-EDFAs, we developed our own MM-EDFA simulator capable of modelling both the Linear Polarized (LP) modes and the full vector solutions. We have concluded that, in practice, the LP amplifier model is valid and sufficient enough to predict the FM-EDFA performance. I proposed a 4-mode-group EDFA design that offered DMG < 1dB across four-mode groups using a customized pump profile. As the number of guided modes increases, the required pump power also increases which means expensive single-mode pump diodes are needed in the core-pumping approach. Cladding pumping is an alternative way to provide pump radiation with the advantages of reducing the costs. Consequently, I upgraded our in-house amplifier simulator to a cladding-pump-able MM-EDFA design tool incorporating an optimization algorithm (i.e. Genetic Algorithm) that accepts customized criteria and allows a large number of free parameters to be optimized simultaneously. Using this tool, I proposed the designs and optimizations of cladding-pumped 4 and 6-mode-group EDFAs. Apart from the standard step-index MM-EDFAs, I also investigated novel fiber amplifiers with ring-index profiles for SDM applications. The first type of ring-index fiber discussed in this thesis is of solid core and weakly guiding. The solid-core ring core fiber has an advantage of reducing digital signal processing complexity in MDM transmission. I proposed a 6-mode-group ring core multimode erbium doped fiber amplifier (RC-MM-EDFA) capable of providing almost identical gain among the six mode groups within the C band using either core- or cladding-pumped implementations. The second type of ring-index fiber is an air-core fiber that enables the stable transmission of Orbital Angular Momentum (OAM) modes, which can be used as another degree of freedom for information multiplexing. I have created a new variant of my amplifier model targeting OAM modes and have achieved DMG lower than 0.5 dB for 12 OAM modes in an air-core EDF.
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Altuncu, Ahmet. "Distributed erbium doped fibre amplifiers (DEDFAs) for use in long haul and high bit rate soliton transmission systems." Thesis, University of Essex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388156.
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Da, Rosa Marcelo Zannin. "Optical gain clamping in erbium doped fibre amplifier : investigation in optical burst switching networks." Thesis, Swansea University, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.678524.
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Pourbahri, Babak. "Erbium-doped fibre amplifiers and their effects on the phase noise of optical carriers and radio-over-fibre signals." Thesis, University of Kent, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.369689.
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Miraz, Mohammad Aleem. "Design of a tuneable multi-wavelength erbium doped fibre laser using periodic filtering and phase modulation." Thesis, University of Strathclyde, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.501865.
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Montes, Thisien Gabriel 1988. "Caracterização experimental de fibras de vidro telurito dopado com érbio e itérbio : Experimental characterization of tellurite glass fibers doped with erbium and ytterbium." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261920.
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Orientador: Aldário Chrestani BordonalliDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Com a demanda por comunicação continuamente aumentando nos últimos anos, mantém-se constante a busca por aperfeiçoamento dos amplificadores ópticos a fibra. Como uma proposta de proporcionar maior largura de banda de amplificação para sistemas ópticos, este trabalho procura caracterizar o comportamento operacional de uma fibra de vidro telurito dopado com érbio e itérbio para diferentes condições iniciais de comprimento de amostra, aplicação de sinais e configuração de bombeio. As amostras, fabricadas pelo Grupo de Fibras Ópticas do IFGW/UNICAMP, foram submetidas a análises experimentais baseadas nas principais topologias de amplificadores a fibra que usam matrizes de sílica. Assim, avalia-se a potencialidade das características de amplificação do vidro telurito fabricado com dosagem de compostos inéditos, além de uma investigação da possibilidade da geração laser utilizando-se essa fibra como meio ativo em configurações com laço de realimentação. Mesmo que o ganho real do sistema não tenha sido determinado pela incerteza em relação a real potência óptica acoplada às amostras, observou-se ser possível a compensação da atenuação que o sinal que se propaga pelas amostras sofre após a aplicação de bombeio. Nesse aspecto, o vidro telurito dopado com érbio e itérbio apresentou potencial de aplicação em amplificação óptica. Uma amostra de 2 cm, comprimento muito menor que o usado em amplificadores ópticos baseados em matrizes de sílica e uma ordem de grandeza menor que os baseados em vidro telurito dopado apenas com érbio, apresentou resultados de ganho óptico on-off da ordem de 30 dB com bombeio bi-direcional de 100 mW. Em relação ao vidro telurito dopado apenas com érbio, os resultados para o ganho on-off chegaram a ser até 15 dB maiores. Além disso, as transições providas pela interação entre a matriz vítrea com o érbio e o itérbio levaram a larguras de banda de 3 dB para o espectro de ASE de até 70 nm, dependendo da configuração de bombeio
Abstract: With the recently increase in data transmission demands, the search for improved fiber amplifier physical processes, materials, and configurations is still on going. As a way to provide a wider amplification bandwidth for optical systems, this work intends to characterize the operational behavior of an erbium and ytterbium doped tellurite fiber for different sample lengths, light coupling and pump configurations. The fiber samples, manufactured by the Optical Fiber Group of the IFGW/UNICAMP, underwent experimental analyses based on the same main pump topologies as those of silica-based optical amplifiers. Thus, the potential amplification characteristics of tellurite glass doped with new compounds are evaluated, as well as an investigation of possible laser generation by using this type of fiber as gain medium within feedback loop configurations. Although real system gain was impossible to determine due to uncertainties in the actual coupled optical power, it was observed that the attenuation during signal propagation through the fiber samples could be compensated after pump application. In this context, the erbium and ytterbium doped tellurite fiber has potential for optical amplification. Samples as short as 2 cm, far shorter than the ones used in silica based amplifiers and one order of magnitude shorter than those based on Er3+ doped tellurite fiber structures, presented on-off optical gain of the order of 30 dB for bi-directional 100-mW pump. By comparing with the latter doped glass structure, the on-off gain results were as high as 15 dB greater. Furthermore, the transitions provided by the interaction between the host glass and both erbium and ytterbium have led to a 70-nm ASE bandwidth, depending on the pumping configuration
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Telecomunicações e Telemática
Mestre em Engenharia Elétrica
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Michel, David Daniel. "Linear-cavity tunable fibre lasers employing an Opto-VLSI processor and a MEMS-based device." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2012. https://ro.ecu.edu.au/theses/520.
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This thesis proposes and demonstrates experimentally two novel linear-cavity tunable fibre lasers employing an erbium-doped fibre (EDF) in conjunction with an Opto- VLSI processor and a MEMS-based device for wavelength selection. The Opto-VLSI processor and the MEMS-based device along with an optical collimator, a Bragg grating plate and an optical lens, enable the realisation of an optical filter for continuous tuning of wavelengths over the amplified spontaneous emission (ASE) range of the EDF. We also propose the use of a section of un-pumped EDF as a saturable absorber (SA), which suppresses noise spikes caused by the high optical pumping power. Experimental results show that by optimising a length of the SA a single wavelength, high power laser signal can be achieved. In addition, we experimentally demonstrate that the performance of the proposed linear-cavity tunable fibre lasers is better than that of ring-cavity tunable laser counterparts. Specifically, we show that linear-cavity based tunable fibre lasers can achieve higher output power, a larger side mode rejection ratio (SMRR) and narrower laser linewidth than ring-cavity tunable fibre lasers.
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Hwang, Bor-Chyuan. "Short erbium doped phosphate fiber amplifiers." Diss., The University of Arizona, 2000. http://hdl.handle.net/10150/289174.
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Spectroscopic properties of high concentration Er³⁺-doped phosphate glasses and performance of short Er³⁺-doped phosphate fiber amplifiers were studied and characterized. Systematic studies of cooperative upconversion of Er³⁺ ions in ⁴I₁₃/₂ level and energy transfer from Yb³⁺ to Er³⁺ in phosphate glasses were performed by a rate equation formalism. The cooperative upconversion coefficient for an Er³⁺ concentration of 4 x 10²⁰ ions/cm³ was found to be 1.1 x 10⁻¹⁸ cm³/s. An energy transfer coefficient of 1.1 x 10⁻¹⁶ cm³/s was found for an Yb³⁺ concentration of 6 x 10²⁰ ions/cm3 and an Er³⁺ concentration of 2 x 10²⁰ ions/cm³. Energy transfer efficiencies from ²F₅/₂ level of Yb³⁺ ions to ⁴I₁₃/₂ level of Er³⁺ ions higher than 95% were determined from our measurements under weak excitation. The performance of high concentration Er³⁺-doped phosphate fiber amplifiers were characterized in terms of gain, noise figure, and signal saturation for a series of active fiber lengths, pump powers, signal input powers, and signal wavelengths. A net gain of 21 dB were achieved in a 71 mm Er³⁺-doped phosphate fiber with a noise figure of ∼5.3 dB by a 980 nm pump power of 244 mW. In addition, a 10 dB net gain can be obtained with a pump power of 110 mW. Performance of short Er³⁺-doped phosphate fiber amplifiers demonstrates the potential for device applications.
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Nelson, Lynn Elizabeth. "Mode-locking of thulium-doped and Erbium-doped fiber lasers." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/32688.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1997.Includes bibliographical references (leaves 140-152).
by Lynn Elizabeth Nelson.
Ph.D.
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VanWiggeren, Gregory D. "Chaotic communication with erbium-doped fiber ring lasers." Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/30299.
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Tamura, Kohichi Robert. "Additive pulse mode-locked erbium-doped fiber lasers." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/11851.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (leaves 155-168).
by Kohichi Robert Tamura.
Ph.D.
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Hu, Yongdan. "High-concentration erbium-doped glasses, fiber amplifiers and lasers." Diss., The University of Arizona, 2001. http://hdl.handle.net/10150/279804.
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Upconversion coefficients in a new high-concentration erbium-doped tellurite glass were obtained a schematic study of experiments and modeling. The upconversion coefficient for ⁴I₁₃/₂ + ⁴I₁₃/₂ → ⁴I₉/₂ + ⁴I₁₅/₂ is found to be 2.74 x 10⁻¹⁸ cm³/s and for ⁴I₁₁/₂ + ⁴I₁₁/₂ → ⁴I₁₅/₂ + ²F₇/₂ is 1.09 x 10⁻¹⁸ cm³/s. The performance of high concentration Er³⁺+-Yb³⁺ -codoped phosphate fiber amplifiers and the performance of a high-power Er³⁺-Yb³⁺-codoped phosphate fiber laser were presented. From a 3.6cm-long fiber, 18 dB internal gain i.e. 5 dB/cm, for small signal input at 1535 nm, was achieved. With a cleaved facet as the output mirror, a fiber laser has been demonstrated from the same fiber with an output power of 33.8 mW at 1549.92 nm. A high slope efficiency of 40.2% was observed. Modeling results of gain and noise figure of four phosphate EDFAs with different lengths were presented with previous measured results. 34% erbium ions were found to be paired in our 3.5wt% erbium-doped phosphate fiber amplifiers. The onset of erbium concentration for pair induced quenching is suggested to be around 3wt% in phosphate fiber amplifiers.
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Palma, Giuseppe. "Design of microlaser in medium infrarer wavelengnth range for biomedicine and environmental monitoring." Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S017/document.
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Les micro-résonateurs optiques comptent parmi les dispositifs les plus importants en photonique. Les résonateurs WGM sont assez particuliers. Il s'agit de composant présentant une symétrie circulaire comme c'est le cas des sphères, des anneaux, des disques et des tores. Les résonateurs WGM présentent un facteur de qualité exceptionnel et un volume modal très faible. Ces appareils peuvent être utilisés dans plusieurs domaines, notamment la télédétection, le filtrage optique et l'optique non linéaire. D'autres applications sont possibles en biologie, médecine, spectroscopie moléculaire, surveillance environnementale, astronomie et astrophysique grâce à l'exploitation du rayonnement moyen infrarouge. Les micro-résonateurs optiques comportent un grand nombre de transitions vibrationnelles qui agissent comme des «empreintes» pour de nombreuses molécules organiques permettant le développement d'applications spectroscopiques innovantes et de nouveaux capteurs. Il convient de noter que l'atmosphère de la terre est transparente au niveau des deux fenêtres de transmission atmosphérique. La première est comprise entre 3 et 5 μm et la seconde entre 8 et 13 μm, ce qui rend possible des applications telles que la détection d'explosifs à distance ainsi que le brouillage de communication confidentielles. La large fenêtre de transparence en verres de chalcogénures dans le domaine spectral infrarouge rend envisageable le développement de nombreuses applications. Les verres de chalcogénure sont caractérisés par une bonne résistance mécanique et une durabilité chimique suffisante dans l'eau et l'atmosphère. Par ailleurs, l'indice de réfraction élevé, le rendement quantique élevé, l'énergie de phonon faible et la solubilité importante des terres rares permettent des émissions dans le domaine spectral du moyen IR. Dans cette thèse, la conception de dispositifs innovants en chalcogénure pour des applications utilisant le moyen infrarouge est étudiée en utilisant un code d'ordinateur personnel formé de façon aléatoire. Les appareils reposent sur des trois types de micro-résonateurs : les microsphères, les micro-disques et les microbulles. Les résonateurs WGM sont efficacement excités à l'aide de fibres nervurées et de guides d'ondes optiques de forme conique. Le nouveau procédé de conception est développé en utilisant la méthode d'optimisation par essaims particulaires (PSO). Elle permet de maximiser le gain d'un amplificateur reposant sur une microsphère d'émission laser dopée à l'erbium à 4,5 μm. Une technique innovante permettant de caractériser les propriétés spectroscopiques de la terre rare intégrant la recherche électromagnétique en mode WGM grâce à l'algorithme PSO a été développée. Les valeurs récupérées sont entachées d’une erreur inférieure à celle prévue par les instruments de mesure ayant un coût élevé. Des applications intéressantes peuvent être obtenues en excitant le micro-résonateur avec une fibre conique présentant deux LPG identiques sur les côtés. En effet, les FLP peuvent sélectionner le couplage de modes de fibre avec le résonateur WGM. En utilisant différentes paires de FLP identiques, opérant dans différentes bandes de longueurs d'onde, il est possible de coupler de façon sélective différents résonateurs à l'aide de la même fibre optique. Un code informatique aléatoire a été développé et validé. Il a démontré la faisabilité d'un capteur de microbulles de glucose. Un microdisque en terre rare dopé est étudié pour obtenir une source de lumière compacte et économique dans l'infrarouge moyen. Un code informatique est développé afin de simuler un micro-disque de terre rare dopé et associé à deux guides d'ondes nervurés, un pour le signal et l'autre pour la pompe. Le modèle est validé à l'aide d'un micro-disque dopée à l'erbium émettant à 4,5 μm. Ce dispositif très prometteur pour des applications dans le moyen infrarouge est obtenu en utilisant un micro-disque de praséodyme dopé émettant à 4,7 μmOptical micro-resonators represent one of the most important devices in photonics. A special kind is constituted by the WGM resonators, i.e. devices with circular symmetry such as spheres, rings, disks and toroids. They are characterized by very small dimensions, exceptionally quality factor and very low modal volume becoming a valuable alternative to the traditional optical micro-resonators, such as Fabry-Pérot cavities. These devices allow applications in several fields, such as sensing, optical filtering and nonlinear optics. In particular, different applications in biology and medicine, molecular spectroscopy, environmental monitoring, astronomy and astrophysics are feasible in Mid-Infrared wavelength range. For example, it includes a lot of strong vibrational transitions that act as “fingerprints” of many bio-molecules and organic species allowing the develop of innovative spectroscopic applications and novel sensors. In addition, the earth's atmosphere is transparent in two atmospheric transmission windows at 3–5 μm and 8–13 μm and then applications such as remote explosive detection, e.g. in airports and for border control, and covert communication systems are feasible. The wide transparency window of chalcogenide glasses in Mid-Infrared makes possible the development of several devices. Chalcogenide glasses are characterized by good mechanical strength and chemically durability in water and atmosphere. Furthermore, the high refractive index, high quantum efficiency, the low phonon energy and high rare-earth solubility enables the emissions at long wavelengths.In this thesis, the design of innovative chalcogenide devices for applications in Mid-Infrared is investigated using an ad-hoc home-made computer code. The devices are based on three kinds of micro-resonators: microspheres, micro-disks and microbubbles. The WGM resonators are efficiently excited by using tapered fiber and ridge waveguides. A novel design procedure is developed using the particle swarm optimization approach (PSO). It allows to maximize the gain of an amplifier based on an erbium-doped microsphere lasing at 2.7 μm.An innovative technique in order to characterize the spectroscopic properties of rare-earth is developed integrating the WGM electromagnetic investigation with PSO algorithm. The method is based on two subsequent steps: in the first one, the geometrical parameters are recovered, in the second one, the spectroscopic parameters. The recovered values are affected by an error less than that provided by high-cost measurement instruments. Furthermore, the procedure is very versatile and could be applied to develop innovative sensing systems.Interesting applications could be obtained exciting the micro-resonator by a tapered fiber with two identical LPGs on the sides. Indeed the LPGs can select the fiber modes coupling with the WGM resonator. Using different pairs of identical LPGs operating in different wavelength bands, it is possible to selective couple different micro-resonators by using the same optical fiber. An ad-hoc computer code is developed and validated and it demonstrated the feasibility of a microbubble glucose sensor.In order to obtain a compact and cost-saving light source in Mid-Infrared, rare-earth doped micro-disk are investigated. A computer code is developed in order to simulate a rare-earth doped micro-disk coupled to two ridge waveguide, one at signal wavelength and the other one at pump wavelength. The model is validated using an erbium-doped micro-disk emitting at 4.5 μm. A very promising device for application in Mid-Infrared is obtained using a praseodymium-doped micro-disk emitting at 4.7 μm
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Šustr, Pavel. "Optický zesilovač v laboratorní výuce." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218165.
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The aim of this thesis is to introduce to reader the application and use of optical EDFA amplifiers in optical transmission and to show wiring and practical test, including measurements on amplifier. The aim of this thesis is to propose the use of optical amplifier in laboratory practice for subject Optical networks. The thesis briefly introduces the problems of data transmissions through optical fibers with a focus on the use of optical amplifiers. The basic characteristic of optical transmission paths and the reasons for the use of optical amplifiers are described here. One entire chapter is devoted to distinction of optical amplifiers. Amplifiers can be divided according to location in the transmission path to the booster, in-line and pre-amplifiers and according to the used of amplifying technology to optical amplifiers with subsidies, semiconductor optical amplifiers and Raman optical amplifiers. The factors affecting the efficiency of optical amplifiers, such as noise and the level of saturated power are mentioned here too. The different types of optical amplifiers from the two producers are also described. From these amplifiers was chosen EDFA CzechLight Amplifier from Optokon to be used for the laboratory exercise in the subject of Optical networks. The use of EDFA optical amplifiers in optical transmission lines is mentioned here too. These amplifiers can be used in telecommunications transmission systems and for data transmission over long distances. They will find use in WDM transmission systems and cable TV distribution through the optical fiber to the end users. Practical measurements were performed on optical amplifier CLA-PB01F. In the transmission route was located attenuator and the dependence of output power to input signal power was measured. The amplification course was linear in the range of input values provided by the manufacturer. Laboratory exercise for the subject of Optical networks is aimed at preacquaintance of students with problems EDFA optical amplifiers and practical measurements with the optical amplifier CLA-PB01F. Students acquire basic theoretical knowledge of the issue and verify the functionality of optical amplifiers on a specific exercise. This work is destined for all who wish to get basic knowledge of optical amplifiers, their characteristics and possibilities of their use in optical transmission lines.
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Bollond, Paul. "Picosecond Pulse Generation and Propagation in Erbium Doped Optical Fibres." Thesis, University of Auckland, 1997. http://hdl.handle.net/2292/1983.
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This thesis is concerned with the generation of picosecond pulses and their propagation through both resonant and non-resonant media. This was achieved by constructing a passively modelocked Erbium doped fibre laser (EDFL) which was used to study pulse propagation through sections of standard communications grade optical fibre, dispersion shifted optical fibre, and also through an Erbium doped fibre amplifier (EDFA) module. The EDFL produced a train of ˜2 psec pulses at 4 MHz, tunable over the erbium gain band ( 1520 - 1570 nm). The laser was constructed from commercially available components and had the property of stability combined with low pump power requirements to produce ˜50 Watt peak power pulses. The laser cavity geometry included a nonlinear optical loop mirror, which has the property of efficiently switching high peak power pulses, and allowed pulsed operation without the aid of any high-speed electronics. An EDFA module of identical geometry to that used in the laser was also constructed, and this was probed using the pulses from the EDFL. The traditional temporal and spectral measurements were found to be inadequate to allow a complete description of the pulse amplification process to be developed. To overcome this problem the technique of frequency resolved optical gating (FROG) was applied for the first time to optical fibre research, and allowed an indirect measurement of the electric field of the pulse. This complete description of the pulse was used in a numerical model to describe pulse propagation in an optical fibre. Fundamental propagation terms in the model were treated as free parameters in a minimisation scheme, which could be determined for a fibre under examination. This technique was shown to be accurate when used to examine pulse propagation through both standard and dispersion shifted optical fibre. A comprehensive numerical model was developed for the EDFA, and it was apparent from this model that a pulse propagating through an optimised EDFA encounters an atomic inversion distribution which is a strong function of distance along the amplifying fibre. It was also shown from the experimental results that the EDFA exhibited resonant dispersion, which is characteristic for propagation through an atomic medium on resonance.
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Williams, Quinton Lemonte. "Fast temporal dynamics of the erbium-doped fiber ring laser." Diss., Georgia Institute of Technology, 1996. http://hdl.handle.net/1853/27975.
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Ono, Shunsuke. "Optical properties and gain characteristics of erbium-doped fiber amplifier." Kyoto University, 2005. http://hdl.handle.net/2433/144986.
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Kyoto University (京都大学)0048
新制・課程博士
博士(人間・環境学)
甲第11688号
人博第294号
新制||人||73(附属図書館)
16||185(吉田南総合図書館)
23331
UT51-2005-D437
京都大学大学院人間･環境学研究科環境相関研究専攻
(主査)教授 村中 重利, 教授 林 哲介, 助教授 田部 勢津久
学位規則第4条第1項該当
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Jin, Cang. "Spatially integrated erbium-doped fiber amplifiers enabling space-division multiplexing." Doctoral thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/27018.
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L'augmentation exponentielle de la demande de bande passante pour les communications laisse présager une saturation prochaine de la capacité des réseaux de télécommunications qui devrait se matérialiser au cours de la prochaine décennie. En effet, la théorie de l’information prédit que les effets non linéaires dans les fibres monomodes limite la capacité de transmission de celles-ci et peu de gain à ce niveau peut être espéré des techniques traditionnelles de multiplexage développées et utilisées jusqu’à présent dans les systèmes à haut débit. La dimension spatiale du canal optique est proposée comme un nouveau degré de liberté qui peut être utilisé pour augmenter le nombre de canaux de transmission et, par conséquent, résoudre cette menace de «crise de capacité». Ainsi, inspirée par les techniques micro-ondes, la technique émergente appelée multiplexage spatial (SDM) est une technologie prometteuse pour la création de réseaux optiques de prochaine génération. Pour réaliser le SDM dans les liens de fibres optiques, il faut réexaminer tous les dispositifs intégrés, les équipements et les sous-systèmes. Parmi ces éléments, l'amplificateur optique SDM est critique, en particulier pour les systèmes de transmission pour les longues distances. En raison des excellentes caractéristiques de l'amplificateur à fibre dopée à l'erbium (EDFA) utilisé dans les systèmes actuels de pointe, l'EDFA est à nouveau un candidat de choix pour la mise en œuvre des amplificateurs SDM pratiques. Toutefois, étant donné que le SDM introduit une variation spatiale du champ dans le plan transversal de la fibre, les amplificateurs à fibre dopée à l'erbium spatialement intégrés (SIEDFA) nécessitent une conception soignée. Dans cette thèse, nous examinons tout d'abord les progrès récents du SDM, en particulier les amplificateurs optiques SDM. Ensuite, nous identifions et discutons les principaux enjeux des SIEDFA qui exigent un examen scientifique. Suite à cela, la théorie des EDFA est brièvement présentée et une modélisation numérique pouvant être utilisée pour simuler les SIEDFA est proposée. Sur la base d'un outil de simulation fait maison, nous proposons une nouvelle conception des profils de dopage annulaire des fibres à quelques-modes dopées à l'erbium (ED-FMF) et nous évaluons numériquement la performance d’un amplificateur à un étage, avec fibre à dopage annulaire, à ainsi qu’un amplificateur à double étage pour les communications sur des fibres ne comportant que quelques modes. Par la suite, nous concevons des fibres dopées à l'erbium avec une gaine annulaire et multi-cœurs (ED-MCF). Nous avons évalué numériquement le recouvrement de la pompe avec les multiples cœurs de ces amplificateurs. En plus de la conception, nous fabriquons et caractérisons une fibre multi-cœurs à quelques modes dopées à l'erbium. Nous réalisons la première démonstration des amplificateurs à fibre optique spatialement intégrés incorporant de telles fibres dopées. Enfin, nous présentons les conclusions ainsi que les perspectives de cette recherche. La recherche et le développement des SIEDFA offriront d'énormes avantages non seulement pour les systèmes de transmission future SDM, mais aussi pour les systèmes de transmission monomode sur des fibres standards à un cœur car ils permettent de remplacer plusieurs amplificateurs par un amplificateur intégré.The exponential increase of communication bandwidth demand is giving rise to the so-called ‘capacity crunch’ expected to materialize within the next decade. Due to the nonlinear limit of the single mode fiber predicted by the information theory, all the state-of-the-art techniques which have so far been developed and utilized in order to extend the optical fiber communication capacity are exhausted. The spatial domain of the lightwave links is proposed as a new degree of freedom that can be employed to increase the number of transmission paths and, subsequently, overcome the looming ‘capacity crunch’. Therefore, the emerging technique named space-division multiplexing (SDM) is a promising candidate for creating next-generation optical networks. To realize SDM in optical fiber links, one needs to investigate novel spatially integrated devices, equipment, and subsystems. Among these elements, the SDM amplifier is a critical subsystem, in particular for the long-haul transmission system. Due to the excellent features of the erbium-doped fiber amplifier (EDFA) used in current state-of-the-art systems, the EDFA is again a prime candidate for implementing practical SDM amplifiers. However, since the SDM introduces a spatial variation of the field in the transverse plane of the optical fibers, spatially integrated erbium-doped fiber amplifiers (SIEDFA) require a careful design. In this thesis, we firstly review the recent progress in SDM, in particular, the SDM optical amplifiers. Next, we identify and discuss the key issues of SIEDFA that require scientific investigation. After that, the EDFA theory is briefly introduced and a corresponding numerical modeling that can be used for simulating the SIEDFA is proposed. Based on a home-made simulation tool, we propose a novel design of an annular based doping profile of few-mode erbium-doped fibers (FM-EDF) and numerically evaluate the performance of single stage as well as double-stage few-mode erbium-doped fiber amplifiers (FM-EDFA) based on such fibers. Afterward, we design annular-cladding erbium-doped multicore fibers (MC-EDF) and numerically evaluate the cladding pumped multicore erbium-doped fiber amplifier (MC-EDFA) based on these fibers as well. In addition to fiber design, we fabricate and characterize a multicore few-mode erbium-doped fiber (MC-FM-EDF), and perform the first demonstration of the spatially integrated optical fiber amplifiers incorporating such specialty doped fibers. Finally, we present the conclusions as well as the perspectives of this research. In general, the investigation and development of the SIEDFA will bring tremendous benefits not only for future SDM transmission systems but also for current state-of-the-art single-mode single-core transmission systems by replacing plural amplifiers by one integrated amplifier.
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Bedö, Stefan. "Erbium doped single-mode fiber lasers: studies on saturation effects /." [S.l : s.n.], 1995. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Fadel, Hicham Joseph. "Tunable erbium-doped fiber ring laser using an intra-cavity filter." Thesis, Texas A&M University, 2004. http://hdl.handle.net/1969.1/1050.
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Linear tuning the frequency of an erbium-doped fiber ring laser using both a Fabry-Perot filter and an electro-optic tunable filter has been experimentally demonstrated. The rate of frequency change is determined by monitoring the fringes produced by laser light transmitted through a fiber Fabry-Perot interferometer. The fiber ring laser has been tuned over a 50 nm spectral range when using the Fabry-Perot filter and a tuning rate of 16480 nm/s has been achieved. The spectral width of the laser is 0.049 nm and the nearest sidelobe to the main peak is more than 30 dB below the central lobe. When the electro-optic tunable filter is used, a spectral range of 11 nm is reached. The spectral width is 2.33 nm and is in close agreement with the filter theoretical results. The sidelobe to main peak difference is around 13 dB.
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Khaleghi, Farideh. "Erbium-doped fiber amplifier applications in WDM transport systems and networks." Thesis, University of Ottawa (Canada), 1996. http://hdl.handle.net/10393/10194.
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New expressions are derived for wavelength-dependent gain variations of the EDFA due to changes in the pump power, total input power, and the power distribution among different wavelength channels in a wavelength-division multiplexing (WDM) system. A simple method is proposed to compensate for the changes in the amplifier gain spectrum. This method is based on adjusting the pump power. Two different novel gain equalization techniques are presented. A tunable coherent optical transversal filter is designed as a gain equalizer. The filter operation is based on coherently combining the tapped signals. It is shown that, although the N tapped signals after being weighted according to the filter parameters are recombined by a tree of 2 x 2 couplers, the coupling loss experienced at the output is much less than the noncoherent coupling loss (10log(N)). For a multi-wavelength input, the spectrum of the amplifier output power is evaluated before and after the equalizer, using the numerical full spectrum model of the amplifier. The impact of the laser phase noise on the performance of this equalizer is studied. Another gain equalization technique is presented where high- and moderate-inversion EDFAs are used alternatively in order to equalize both signal power and signal-to-noise ratio (SNR) of multiple wavelength channels in WDM transmission systems. This technique is based on the fact that the gain slope is a function of the inversion level in amplifiers. This is confirmed experimentally. The performance of the equalized WDM system is examined by a numerical analysis based on the full spectrum model of the amplifier. The interferometric conversion of the phase-to-intensity noise is studied. The probability density function (pdf) of the intensity noise at the output of a multi-tap filter is derived. The degradation of the filter response is evaluated. The power penalty due to this noise is derived for amplitude modulated signals modulated using different bit rates. The power penalty due to interferometric noise caused by multiple reflections is also derived. A novel bidirectional EDFA configuration is proposed where the power penalty associated with the amplifier due to both the signal-spontaneous noise and the interferometric noise is substantially reduced. The experimental results are presented where a gain of 36 dB is achieved, and a 2.5 Gb/s bidirectional transmission over 300 km is realized. The power penalty is as low as 0.5 dB. Application of EDFA in an optical network is presented. The multi-access scheme in this local network is code-division multiple access (CDMA). A new correlator receiver architecture for noncoherent optical CDMA networks is proposed based on a modified version of unipolar-bipolar correlation functions for known bipolar codes. These functions are studied. Average bit error rate (BER) performance is evaluated for this architecture. The results indicate that bipolar capacity can be achieved by this architecture.
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Baker, Colin C., E. Joseph Friebele, Charles G. Askins, Michael P. Hunt, Barbara A. Marcheschi, Jake Fontana, John R. Peele, et al. "Nanoparticle doping for improved Er-doped fiber lasers." SPIE-INT SOC OPTICAL ENGINEERING, 2016. http://hdl.handle.net/10150/622710.
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A nanoparticle (NP) doping technique was used for making erbium-doped fibers (EDFs) for high energy lasers. The nanoparticles were doped into the silica soot of preforms, which were drawn into fibers. The Er luminescence lifetimes of the NP-doped cores are longer than those of corresponding solution-doped silica, and substantially less Al is incorporated into the NP-doped cores. Optical-to-optical slope efficiencies of greater than 71% have been measured. Initial investigations of stimulated Brillouin scattering (SBS) have indicated that SBS suppression is achieved by NP doping, where we observed a low intrinsic Brillouin gain coefficient, of similar to 1x 10(-11) m/W and the Brillouin bandwidth was increased by 2.5x compared to fused silica.
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Szkopek, Thomas. "Experiment and theory of a novel, multiple wavelength, erbium-doped fiber laser." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ63033.pdf.
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Rotili, Roberto. "On the stability of multi-wavelength mode-locked erbium-doped fiber lasers." Thesis, McGill University, 2004. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=82627.
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Presented in this thesis is a novel systematic approach to determine the general characteristics and stability of an EDFL, and a thorough experimental investigation of a mode-locked dual-wavelength EDFL.The novel method to characterize an EDFL consists of performing an extensive set of measurements, and from these measurements a set of parameters is calculated. These parameters quantifiably describe the laser in terms of its temporal and spectral characteristics, signal power and wavelength variations, and number of occurrences for which the laser ceases its multi-wavelength operation.
An experimental investigation of a free-running mode-locked dual-wavelength EDFL with different signal wavelength spacing and pulse chirps is performed with the characterization method proposed in this thesis.
The original conclusions that are drawn from the experimental investigation of an EDFL are that the stability of the EDFL exponentially decreases as a function of the signal wavelength spacing, and the stability of an EDFL is improved with linearly chirped FBGs.
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LIMA, RODOLFO ARAUJO DE AZEVEDO. "SIMULATION AND PERFORMANCE ANALYSIS OF DIGITAL SYSTEMS USING ERBIUM-DOPED FIBER AMPLIFIERS." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 1996. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=8869@1.
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TELECOMUNICAÇÕES BRASILEIRAS S/AOs amplificadores a fibra dopada com érbio (EDFAs) têm se mostrado como uma alternativa bastante atraente para aumentar a capacidade de sistemas de comunicações por fibras ópticas operando na terceira janela de transmissão de fibras convencionais (lambda = 1.55 mi m). Consideráveis esforços têm sido direcionados ao aprimoramento do desempenho desses dispositivos. O potencial de aplicação em telecomunicações é grande e motiva o estudo do desempenho dos enlaces com o uso de EDFAs. A maior parte das contribuições teóricas sobre influência de amplificadores ópticos no desempenho dos receptores consiste de métodos que são fáceis de usar mas muito aproximado - o que pode conduzir a estimativas bastantes imprecisas -, ou muito precisos mas de utilização extremamente difícil - devido a uma complexidade inerente. São apresentados modelos para a simulação de sistemas de comunicações ópticos digitais que consideram as perdas no sinal e as distorções da forma de onda devidas ao efeito combinado do chirping do laser, da dispersão da fibra e da largura de banda finita do receptor. É proposta uma nova abordagem para o cálculo da taxa de erro do sistema e da sensibilidade, que possui a precisão e a simplicidade desejadas. O método desenvolvido considera a interferência intersimbólica (causada pelas distorções) e das contribuições de ruídos dos amplificadores, utilizando-se o método semi-analítico. Esses modelos e o método desenvolvido foram utilizados para introduzir a simulação de sistemas ópticos com EDFAs em um programa já existente de análise de sistemas. Foram realizadas simulações para avaliar as contribuições dos diversos parâmetros dos EDFAs e as implicações de algumas propriedades do sistema no desempenho total do sistema óptico. A comparação com resultados de análises rigorosas, encontrados na literatura, validou a abordagem proposta.
Erbium-doped fiber amplifiers (EDFAs) have shown to be a very attractive alternative to improve the capacity of optical-fiber communications systems operating in the third transmission window of conventional fibers (lambda = 1.55 mi m). Considered efforts have been made towards the performance enhancement of these devices. The possible application potential in telecommunications is indeed large, and has simulated the study of system performance using EDFAs. Most of the previous theoretic contribuitions on the influence of optical amplifiers in the receiver performance consist of methods that are either easy to use but over-approximated - what can lead to quite inaccurate evaluations - or very precise but extremely difficult to use - due to some inherent complexity. Models for the simulation of digital optical communication systems are presented, which account for signal loss and distortion - due to laser chirping, fiber dispersion and detector finite bandwidth. A new semi-analytical method for the evaluation of bit-error rate (BER) and receiver sensitivity is introduced, which possesses the desired accuracy and simplicity. It takes into account the presence of inter-symbol interference (due to signal distortion) and the optical amplifier noises. These modesl and the developed method jhave been the used for introducing simulation of optical systems with EDFAs into a previously existing system evaluation software package. A numbe of simulations was carried out in order to estimate the contribution of EDFA parameters and implications of some system properties in the final performance of the optical system. The comparison with results from rigorous analysis, found in the literature, has validated the proposed approach.
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Tan, Jessica Sinyin 1977. "Noise performance of erbium-doped fiber amplifiers with forward and reverse plumbing." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86506.
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Thesis (S.B. and M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2000.Includes bibliographical references (p. 59-62).
by Jessica Sinyin Tan.
S.B.and M.Eng.
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Botha, Roelene. "Towards an integrated optic tuneable gain equalizer for erbium-doped fibre amplifiers." Thesis, 2009. http://hdl.handle.net/10210/2153.
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M.Ing.Long distance optical communication systems experience a large degree of attenuation due to fibre losses, necessitating signal amplification. Erbium Doped Fibre Amplifiers (EDFAs) have found widespread use as all-fibre optical amplifiers, but exhibit unequal amplification of different wavelengths. Since the gain spectrum is signal-power and pump-power dependent, each EDFA spectrum may differ considerably, and a tuneable gain equalizer is required. A tuneable long-period grating (LPG) can be implemented as a gain equalizer for EDFAs. This dissertation deals with the design of an integrated optic version of the tuneable equalizing filter. The various components of which the device comprises, including optical couplers, Mach-Zehnder interferometers and an LPG, are investigated. The integrated optics designs of these components are then done using the BeamPROP software package. The use and optical properties of germania-doped silica as photosensitive waveguide material is studied. The production of the films for the gain equalizer, using electron-cyclotron resonance plasma-enhanced chemical vapour deposition, is discussed. Characterization of these films was carried out using spectroscopic ellipsometry and infrared spectroscopy. The optical constants, thickness, germania content and hydroxyl absorption was calculated using these measurements.
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Nhlapo, Thabiso J. "Gain equalization of erbium doped fibre amplifiers with tuneable long-period gratings." Thesis, 2009. http://hdl.handle.net/10210/2176.
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M.Ing.This thesis is about the gain equalization of erbium doped fibre amplifiers (EDFA), which is a key technology for enabling wavelength-division multiplexed (WDM) optical communication systems. In order to flatten dynamically the EDFA gain spectrum, a tuneable long-period grating filter was demonstrated. Long-period gratings were fabricated by using a KrF excimer laser combined with the metal amplitude mask technique. The transmission spectrum characteristic of the long- period grating was simulated theoretically by the coupled-mode theory. The coupling between the core and cladding modes of the long-period grating was investigated both experimentally and theoretically. The EDFA was constructed by using the forward pumping configuration consisting of pump laser source, WDM couplers, an optical isolator, and the erbium-doped fibre. The EDFA was characterized theoretically and experimentally for WDM applications. The tuneable long-period grating filter design is based on the tuneable coupler that uses the Mach-Zehnder interferometer configuration. The tuneable filter was demonstrated by equalizing the EDFA gain spectrum and the amplified spontaneous emission (ASE) source. The main advantage of this filter compared to other optical filters is its tuneability of the attenuation over a wide range of pump power.
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Kaboko, Jean-Jacques Monga. "Design and development of an all-optical active Q-switched Erbium-doped fibre ring laser." Thesis, 2012. http://hdl.handle.net/10210/5348.
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M.Phil.This dissertation describes the design and experimental realization of an all-optical active Q-switched Erbium-doped fibre ring laser. The aim of this research is to propose an approach of Q-switching mechanism for a fibre laser. The Q-switch device combines a fibre Bragg grating and a tunable fibre Fabry-Perot filter. The Q-switching principle is based on dynamic spectral overlapping of two filters, namely FBG based filter and tunable F-P filter. When the spectra overlap, the filter system has the maximum transparency, the laser cavity has minimal losses and it can release the stored power in the form of the giant impulse. A series of experiments are performed to optimize the all-optical active Q-switched Erbium-doped ring laser system in term of output peak power and time duration of laser pulses. Two different Erbium-doped fibres having different Erbium ion concentration are used in this experimental investigation. The first fibre, with an Erbium ion concentration of 2200 ppm and pump absorption of 23.4 at 980 nm is referred to as “high concentration” and the second with an Erbium ion concentration of 960 ppm and pump absorption of 12.4 at 980 nm is referred to as “low concentration” To optimize the Q-switched fibre laser system, different parameters were investigated such as the length of the Erbium-doped fibre, the output coupling ratio, the repetition rate of pulses and the concentration of the Erbium Doped Fibres. The achieved output laser pulse characteristics, peak power and time duration, were 580 mW and 13 μs respectively, at 1 kHz of repetition rate. These characteristics were obtained using a length of 3.5 m “low concentration” Erbium-doped fibre in a ring laser cavity; the output coupling is 90 %, for a pump power of 80 mW. Employing this all-optical Q-switching approach, a simple, robust all-optical active Q-switched Erbium-doped laser is demonstrated.
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Liang, Chung-Chih, and 梁仲志. "Erbium Doped Fiber Ring Laser." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/58857845907346718303.
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碩士中原大學
應用物理研究所
93
ABSTRACT Demonstrated here is a fiber ring laser based on 980 nm diode laser pumping ring-type configuration including a coupler and erbium-doped fiber (EDF) with single Brag-fiber grating. The optimized simulation is carried out to optimize the output power, by changing the length and the doping concentration of the EDF, the ratio of the reflection, the number and the position of the isolators. We also investigate and compare the various EDFs of different companies. The EDF of Fiber core has the best output power and the most stability of the power and the center wavelength.
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Chen, Chih-Yang, and 陳智揚. "Femtosecond erbium-doped fiber amplifier." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/xnyhav.
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碩士國立清華大學
光電工程研究所
105
In this thesis, we utilize a pulse shaper to control the spectral phase of the pulse seeded to a commercial Erbium-Doped Fiber Amplifier (EDFA) system, and seek to maximize the peak power and minimize the duration of the output pulse. In theory, nonlinear effects can be suppressed when the pulse remains highly chirped during the amplification process. However, in our experiment the EDFA is composed of relatively long EDF [40 meters] compare to typical fiber amplifiers [roughly 3-5 meters], nonlinear effects still play important roles as noticeable spectral broadening is observed. In our work, an input pulse with 7.7 mW average power, 8.3 MHz repetition rate and 660 fs transform-limited (TL) pulse width [defined by full-width at half maximum (FWHM)] is seeded to our EDFA system [with 1.5 W pump power]. Amplified pulses with average power of 155 mW [before compression] and peak power of 235 kW [after ideal phase compensation] is generated when a group delay dispersion (GDD) of 3.285 ps2 is applied to the seed pulse via a pulse shaper.
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Hsu, Yaw-Wen, and 許耀文. "Applications of Erbium-Doped Fiber Amplifier." Thesis, 2002. http://ndltd.ncl.edu.tw/handle/62932162210223025330.
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碩士國立交通大學
光電工程所
90
In order to ensure the transmission quality of WDM systems, the optical amplifier used in WDM system should have properties such as wide bandwith, high output power and low noise figure. However, with the development of long-haul fiber transmission system, the gain-flattening technique should also be upgraded. So dynamic gain flattening technique is needed. In the first part of the thesis, we use a Fabry-Perot laser diode integrated into an erbium-doped fiber amplifier structure. By multi-wavelength injection, dynamic gain flattening and gain clamping can be simultaneously achieved. The experimental results show a good performance, in which the flatness can be less than 2 dB in the range of 1530~1560 nm. As for the second part, we take advantage of the properties of gain clamping and develop a new structure. In this structure, we can monitor the power of each channel in fiber communication networks by scanning the slope of gain curve. From the experimental results, the maximum inaccuracy is about 0.8 dB.
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Xu, Shi-Wen, and 徐世文. "Dynamic characteristic of erbium doped fiber amplifier." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/03063388640545576447.
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Ye, Meng-Shu, and 葉孟書. "Inhomogeneous broadening in erbium-doped fiber amplifiers." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/78613999231919913528.
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