Search results for "Nonlinear"
showing 10 items of 3684 documents
Galerkin Scheme-Based Determination of Survival Probability of Oscillators With Fractional Derivative Elements
2016
In this paper, an approximate semi-analytical approach is developed for determining the first-passage probability of randomly excited linear and lightly nonlinear oscillators endowed with fractional derivative elements. The amplitude of the system response is modeled as one-dimensional Markovian process by employing a combination of the stochastic averaging and the statistical linearization techniques. This leads to a backward Kolmogorov equation which governs the evolution of the survival probability of the oscillator. Next, an approximate solution of this equation is sought by resorting to a Galerkin scheme. Specifically, a convenient set of confluent hypergeometric functions, related to …
Amplifier similariton fibre laser with nonlinear spectral compression
2012
We propose and numerically demonstrate a new concept of fibre laser architecture supporting self-similar pulse evolution in the amplifier and nonlinear pulse spectral compression in the passive fibre. The latter process is beneficial for improving the power efficiency as it prevents strong spectral filtering from being highly dissipative.
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.
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…
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.
Parametric frequency conversion of optical simulton pulses
2007
We present an analytical description of the parametric frequency conversion of short solitary wave optical pulses in quadratic nonlinear crystals controlled by means of a continuous wave background.
Emergence of extreme events in fiber-based parametric processes driven by a partially incoherent pump wave
2009
Modulation instability (MI) generated by a picosecond coherent pulse has been recently identified as the key element of the generation of optical rogue-waves in supercontinuum-based systems [1]. Similar rare but highly energetic pulse structures can also appear in non-solitonic configurations such as Raman amplifiers driven by a partially incoherent pump wave propagating in fibres with low group velocity dispersion [2]. Therefore, one may wonder whether optical rogue-like event can also occur in MI-based amplifier because both Raman and parametric amplifiers benefit from a quasi-instantaneous gain. We provide here experimental evidence of rare optical events in a parametric amplifier in pre…
Observation of a nonlinear microfiber resonator
2008
Measurements of the intensity transfer function of a silica microfiber resonator are shown to follow a wide variety of hysteresis cycles, depending on the cavity detuning and the scanning frequency of the range of input powers. We attribute these observations to a nonlinear phase shift of thermal origin and provide a simple model that reproduces well our measurements. The response time is found to be around 0.6 ms.