1,563 research outputs found
Design of Radiation-Hardened Rare-Earth Doped Amplifiers Through a Coupled Experiment/Simulation Approach
We present an approach coupling a limited experimental number of tests with numerical simulations regarding the design of radiation-hardened (RH) rare earth (RE)-doped fiber amplifiers. Radiation tests are done on RE-doped fiber samples in order to measure and assess the values of the principal input parameters requested by the simulation tool based on particle swarm optimization (PSO) approach. The proposed simulation procedure is validated by comparing the calculation results with the measured degradations of two amplifiers made with standard and RH RE-doped optical fibers, respectively. After validation, the numerical code is used to theoretically investigate the influence of some amplifier design parameters on its sensitivity to radiations. Simulations show that the RE-doped fiber length used in the amplifier needs to be adjusted to optimize the amplifier performance over the whole space mission profile rather than to obtain the maximal amplification efficiency before its integration in the harsh environment. By combining this coupled approach with the newly-developed RH RE-doped fibers, fiber-based amplifiers nearly insensitive to space environment may be designed in the future
Coupled experiment/simulation approach for the design of radiation-hardened rare-earth doped optical fibers and amplifiers
We developed an approach to design radiation-hardened rare earth -doped fibers and amplifiers. This methodology combines testing experiments on these devices with particle swarm optimization (PSO) calculations. The composition of Er/Yb-doped phosphosilicate fibers was improved by introducing Cerium inside their cores. Such composition strongly reduces the amplifier radiation sensitivity, limiting its degradation: we observed a gain decreasing from 19 dB to 18 dB after 50 krad whereas previous studies reported higher degradations up to 0°dB at such doses. PSO calculations, taking only into account the radiation effects on the absorption efficiency around the pump and emission wavelengths, correctly reproduce the general trends of experimental results. This calculation tool has been used to study the influence of the amplifier design on its radiation response. The fiber length used to ensure the optimal amplification before irradiation may be rather defined and adjusted to optimize the amplifier performance over the whole space mission profile rather than before integration in the harsh environments. Both forward and backward pumping schemes lead to the same kind of degradation with our active fibers. By using this promising coupled approach, radiation-hardened amplifiers nearly insensitive to radiations may be designed in the future
Low noise all-fiber amplification of a coherent supercontinuum at 2 \mu m and its limits imposed by polarization noise
We report the amplification of an all-normal dispersion supercontinuum pulse
in a Thulium / Holmium co-doped all-fiber chirped pulse amplification system.
With a -20 dB bandwidth of more than 300 nm in the range 1800-2100 nm the
system delivers high quality 66 fs pulses with more than 70 kW peak power
directly from the output fiber. The coherent seeding of the entire emission
bandwidth of the doped fiber and the stability of the supercontinuum generation
dynamics in the silicate glass all-normal dispersion photonic crystal fiber
result in excellent noise characteristics of the amplified ultrashort pulses
Electrospun amplified fiber optics
A lot of research is focused on all-optical signal processing, aiming to
obtain effective alternatives to existing data transmission platforms.
Amplification of light in fiber optics, such as in Erbium-doped fiber
amplifiers, is especially important for an efficient signal transmission.
However, the complex fabrication methods, involving high-temperature processes
performed in highly pure environment, slow down the fabrication and make
amplified components expensive with respect to an ideal, high-throughput and
room temperature production. Here, we report on near infrared polymer fiber
amplifiers, working over a band of about 20 nm. The fibers are cheap, spun with
a process entirely carried out at room temperature, and show amplified
spontaneous emission with good gain coefficients as well as low optical losses
(a few cm^-1). The amplification process is favoured by the high fiber quality
and low self-absorption. The found performance metrics promise to be suitable
for short-distance operation, and the large variety of commercially-available
doping dyes might allow for effective multi-wavelength operation by electrospun
amplified fiber optics.Comment: 27 pages, 8 figure
Performance analysis of HG_EDFA and LN_EYCDFA
The scope of this paper is to analyze the performance of HG_EDFA (High Gain Erbium Doped Fiber Amplifier) and LN_EYCDFA (Less ASE Noise erbium-ytterbium co-doped fiber amplifier) using single pumping with the wavelength of 980nm by the various parameters like Gain, forward output signal power and forward and backward ASE (Amplified spontaneous Emission) noise power. This Paper describes the simulation models of HG_EDFA is connected with an input of (DMLaser1) direct modulated laser source and the performance was analyzed with the parameters were measured and the values are tabulated and plotted and compared with LN_EYCDFA. The simulation model consists of input source 1mw with wavelength (1550nm), pumping CW Laser source with wavelength 980nm and Filter. The resulting models were accurately represents Gain and optimized output signal power. Simulation results shows that by choosing careful fiber length 20m and pump power 1mw in single pumping gives ASE noise 0.0025mw in HG_EDFA and 12X10-14mw in LN_EYCDFA
Spatially integrated erbium-doped fiber amplifiers enabling space-division multiplexing
L'augmentation exponentielle de la demande de bande passante pour les communications laisse prĂ©sager une saturation prochaine de la capacitĂ© des rĂ©seaux de tĂ©lĂ©communications qui devrait se matĂ©rialiser au cours de la prochaine dĂ©cennie. En effet, la thĂ©orie de lâinformation prĂ©dit que les effets non linĂ©aires dans les fibres monomodes limite la capacitĂ© de transmission de celles-ci et peu de gain Ă ce niveau peut ĂȘtre espĂ©rĂ© des techniques traditionnelles de multiplexage dĂ©veloppĂ©es et utilisĂ©es jusquâĂ prĂ©sent dans les systĂšmes Ă haut dĂ©bit. La dimension spatiale du canal optique est proposĂ©e comme un nouveau degrĂ© de libertĂ© qui peut ĂȘtre utilisĂ© pour augmenter le nombre de canaux de transmission et, par consĂ©quent, rĂ©soudre cette menace de «crise de capacité». Ainsi, inspirĂ©e par les techniques micro-ondes, la technique Ă©mergente appelĂ©e multiplexage spatial (SDM) est une technologie prometteuse pour la crĂ©ation de rĂ©seaux optiques de prochaine gĂ©nĂ©ration. Pour rĂ©aliser le SDM dans les liens de fibres optiques, il faut rĂ©examiner tous les dispositifs intĂ©grĂ©s, les Ă©quipements et les sous-systĂšmes. Parmi ces Ă©lĂ©ments, l'amplificateur optique SDM est critique, en particulier pour les systĂšmes de transmission pour les longues distances. En raison des excellentes caractĂ©ristiques de l'amplificateur Ă fibre dopĂ©e Ă l'erbium (EDFA) utilisĂ© dans les systĂšmes actuels de pointe, l'EDFA est Ă nouveau un candidat de choix pour la mise en Ćuvre des amplificateurs SDM pratiques. Toutefois, Ă©tant donnĂ© que le SDM introduit une variation spatiale du champ dans le plan transversal de la fibre, les amplificateurs Ă fibre dopĂ©e Ă l'erbium spatialement intĂ©grĂ©s (SIEDFA) nĂ©cessitent une conception soignĂ©e. Dans cette thĂšse, nous examinons tout d'abord les progrĂšs rĂ©cents du SDM, en particulier les amplificateurs optiques SDM. Ensuite, nous identifions et discutons les principaux enjeux des SIEDFA qui exigent un examen scientifique. Suite Ă cela, la thĂ©orie des EDFA est briĂšvement prĂ©sentĂ©e et une modĂ©lisation numĂ©rique pouvant ĂȘtre utilisĂ©e pour simuler les SIEDFA est proposĂ©e. Sur la base d'un outil de simulation fait maison, nous proposons une nouvelle conception des profils de dopage annulaire des fibres Ă quelques-modes dopĂ©es Ă l'erbium (ED-FMF) et nous Ă©valuons numĂ©riquement la performance dâun amplificateur Ă un Ă©tage, avec fibre Ă dopage annulaire, Ă ainsi quâun amplificateur Ă double Ă©tage pour les communications sur des fibres ne comportant que quelques modes. Par la suite, nous concevons des fibres dopĂ©es Ă l'erbium avec une gaine annulaire et multi-cĆurs (ED-MCF). Nous avons Ă©valuĂ© numĂ©riquement le recouvrement de la pompe avec les multiples cĆurs de ces amplificateurs. En plus de la conception, nous fabriquons et caractĂ©risons une fibre multi-cĆurs Ă quelques modes dopĂ©es Ă l'erbium. Nous rĂ©alisons la premiĂšre dĂ©monstration des amplificateurs Ă fibre optique spatialement intĂ©grĂ©s incorporant de telles fibres dopĂ©es. Enfin, nous prĂ©sentons les conclusions ainsi que les perspectives de cette recherche. La recherche et le dĂ©veloppement des SIEDFA offriront d'Ă©normes avantages non seulement pour les systĂšmes de transmission future SDM, mais aussi pour les systĂšmes de transmission monomode sur des fibres standards Ă un cĆur car ils permettent de remplacer plusieurs amplificateurs par un amplificateur intĂ©grĂ©.The exponential increase of communication bandwidth demand is giving rise to the so-called âcapacity crunchâ 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 âcapacity crunchâ. 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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