Search results for "Amplifier"

Backward frequency doubling of near infrared picosecond pulses.

2014

We report on backward second-harmonic generation using ps laser pulses in congruent lithium niobate with 3.2 µm periodic poling. Three resonant peaks were measured between 1530 and 1730 nm, corresponding to 16th, 17th and 18th quasi-phase-matching orders in the backward configuration, with a conversion efficiency of 4.75 x 10(-5%)/W for the 16th order. We could also discriminate the contributions from inverted domains randomized in duty-cycle.

Control processes for stimulated Raman scattering in optical fibers by dual-frequency pumping

1998

We pointed out that with nondegenerate frequency, and orthogonally polarized pump waves, the SRS may be suppressed in one of the axes of a highly birefringent fiber either via a four wave mixing (FWM) parametric process, or through the orthogonal component of the Raman nonlinearity.

A Theoretical Approach to the Risken-Nummedal Instability in Erbium-Doped Fibre Lasers

2005

Radiation hardening techniques for rare-earth-based optical fibers and amplifiers

2012

Er/Yb doped fibers and amplifiers have been shown to be very radiation sensitive, limiting their integration in space. We present an approach including successive hardening techniques to enhance their radiation tolerance. The efficiency of our approach is demonstrated by comparing the radiation responses of optical amplifiers made with same lengths of different rare-earth doped fibers and exposed to gamma-rays. Previous studies indicated that such amplifiers suffered significant degradation for doses exceeding 10 krad. Applying our techniques significantly enhances the amplifier radiation resistance, resulting in a very limited degradation up to 50 krad. Our optimization techniques concern …

Comparison of asymmetric and symmetric cavity configurations of erbium-doped fiber laser in active Q-switched regime

2012

We present a comparative analysis of the dynamics of an actively Q-switched erbium-doped fiber laser assembled in two configurations of Fabry–Perot cavity, asymmetric and symmetric, specified by the location of an acousto-optic Q-switch modulator relative to the output couplers. In both configurations, the length of an active (Er3+-doped) fiber is chosen such that the laser does not spuriously emit at the moments when the modulator is blocked, which is important for the pulse-on-demand operation. We show experimentally that the symmetric cavity configuration permits enlarging of the active fiber length twice as compared to the asymmetric one, thereby increasing the energy and decreasing the…

Bidirectional laser cavity solitons

2007

Cavity solitons in optical systems have been studied for two decades in a large variety of optical systems. In principle, bidirectional lasers can emit only unidirectionally in steady state, as the two-mode solution (non null steady state in the two possible emission directions) is an unstable solution (winner-takes-all competition prevents the bidirectional cw emission). But for a wide aperture cavity this is not necessarily true as, in different regions of the transverse (with respect to the propagation axis) direction, emission in different propagation directions could occur if the fronts separating these domains are stable. In fact this is exactly what happens when the cavity losses for…

Asymptotic characteristics of parabolic similariton pulses in optical fiber amplifiers

2004

The fundamental asymptotic nature of parabolic similariton pulses in normal-dispersion fiber amplifiers is experimentally demonstrated. With frequency-resolved optical gating characterization measurements with a fixed input pulse energy, the output parabolic pulse characteristics are shown to be invariant with the input pulse profile and duration and to be completely determined only by the amplifier parameters.

Emergence of extreme events in fiber-based nonlinear devices

2010

We review our experimental and theoretical results showing the emergence of rogue events during light propagation in fiber-based nonlinear systems. Distinct statistical properties are underlined through parametric and Raman amplifications, supercontinuum generation and optical turbulence.

Vector π pulse soliton in coherent optical amplifiers

2007

We found a novel type of vector soliton pulse in a medium with linear loss and nonlinear gain from the coherent resonant interaction of light with two-level atoms exhibiting a degenerate upper state.

Interaction between optical parabolic pulses in a Raman fiber amplifier

2009

We investigate the interaction between optical parabolic pulses in a Raman fiber amplifier. Self-similar amplification of two identical time-delayed pulses creates an oscillation which further evolves into a train of dark solitons through the combined effects of non-linearity, normal dispersion and adiabatic Raman gain. Theoretical predictions are in good agreement with experimental results.