Search results for " amplifiers"
showing 10 items of 42 documents
Universal charts for optical difference frequency generation in the terahertz domain
2010
We present a universal and rigorous approach to study difference frequency generation in the terahertz domain, keeping the number of degrees of freedom to a minimum, through the definition of a suitable figure of merit. The proposed method relies on suitably normalized charts, that enable to predict the optical-to-terahertz conversion efficiency of any system based on wave propagation in quadratic nonlinear materials. The predictions of our approach are found to be in good agreement with the best experimental results reported to date, enabling also to estimate the d22 nonlinear coefficient of high quality GaSe.
Real time measurement of long parabolic optical similaritons
2008
International audience; Long optical similaritons using a Raman fibre amplifier are generated. These pulses, with a highly parabolic profile, are monitored in real time on a high speed oscilloscope. Tunability of both the temporal and spectral widths of the pulses is then investigated.
Extreme statistics in Raman fiber amplifiers : influence of pump depletion and dispersion
2010
OSA 2010 NonLinear Photonics Best Student Poster Award; International audience; We experimentally and theoretically investigate the influence of pump depletion effects on extreme statistics observed in fiber Raman amplifiers. We also report on the impact of the dispersion of the fiber.
Coupled experiment/simulation approach for the design of radiation-hardened rare-earth doped optical fibers and amplifiers
2011
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, co…
Parabolic pulse generation and applications
2009
Parabolic pulses in optical fibers have stimulated an increasing number of applications. We review here the physics underlying the generation of such pulses as well as the results obtained in a wide-range of experimental configurations.
Multidimensional shaping of spatiotemporal waves in multimode nonlinear fibers
2019
Recent experiments have shown that nonlinear wave propagation in multimode optical fibers leads to complex spatio-temporal phenomena. In this talk, we introduce new approaches for the control and optimization of nonlinear beam reshaping in the spatial, temporal and spectral dimensions. The first approach applies to spatial beam self-cleaning the technique of transverse wavefront shaping, which permits to launch an optimized input mode combination, that results in the stable generation of a whole nonlinear mode alphabet at the fiber output. The second approach introduces a longitudinal tapering of the core diameter of multimode active and passive fibers, which permits to generate ultra-wideb…
Generation of parabolic pulses and applications for optical telecommunications
2009
International audience; Parabolic pulses in optical fibers have stimulated an increasing number of applications. We review here the physics underlying the generation of such self-similar pulses as well as the results obtained in a wide-range of passive or active experimental configurations.
Pulse transition to similaritons in normally dispersive fibre amplifiers
2013
selected by the editors of Journal of Optics as a Highlight of 2013a video linked to the experiments can be seen at : http://youtu.be/thbXaW91D5g; International audience; A detailed experimental characterization of the transition process of an initially Gaussian pulse to the asymptotic self-similar parabolic solution in optical fibre amplifiers operating in the normal dispersion regime is performed.
Performance analysis of dual-pump nonlinear amplifying loop mirror mode-locked all-fibre laser
2019
We numerically characterise, in the three-dimensional space of adjustable cavity parameters, the performance of a recently reported layout of a flexible figure-8 laser having two independently pumped segments of active fibre in its bidirectional ring (Smirnov et al 2017 Opt. Lett. 42 1732–5). We show that this optimisation problem can be efficiently addressed by applying a regression model based on a neural-network algorithm.
Synthetic approach to the design of wide-band microwave injection-locked amplifiers
2010
In this work, a synthesis-based approach to the realization of wide-band microwave injection-locked amplifiers (ILA) is proposed. To this purpose, a transmission-type topology is combined with a feedback structure in which the "core ILA" is intentionally separated from the output (power) amplifier. A modular, matched, design of individual building blocks of the core ILA is then adopted, which allows their first-approximation exact modeling in the dynamical complex-envelope domain, following the theory earlier developed by Calandra-Sommariva. On this basis, analytic expressions for the main operating characteristics of the ILA (such as the locking bandwidth under small signal operation) are …