Search results for "brillouin scattering"
showing 10 items of 30 documents
Optical rogue-wave-like extreme value fluctuations in fiber Raman amplifiers
2008
International audience; We report experimental observation and characterization of rogue wave-like extreme value statistics arising from pump-signal noise transfer in a fiber Raman amplifier. Specifically, by exploiting Raman amplification with an incoherent pump, the amplified signal is shown to develop a series of temporal intensity spikes whose peak power follows a power-law probability distribution. The results are interpreted using a numerical model of the Raman gain process using coupled nonlinear Schrödinger equations, and the numerical model predicts results in good agreement with experiment.
An experimental analysis of self-Q-switching via stimulated Brillouin scattering in an ytterbium doped fiber laser
2013
An experimental study of self-Q-switching (SQS) in an ytterbium doped fiber laser (YDFL) arranged using a twin-core GTWave assembly is reported. The main mechanisms that initiate, amplify, and limit SQS pulses in amplitude are revealed to be stimulated Brillouin and Raman scattering (SBS/SRS) and Yb3+ amplified spontaneous emission. The parameters featuring SQS oscillation in terms of efficiency and stability of pulsing are found to be intra-cavity loss and feedback strength. An analysis of the YDFL SQS regime?s features?pulsing time series, optical and RF spectra, amplitude and timing jitter?is provided for the two experimental situations: (i) when SQS pulsing stochastically intermits with…
Kerr self-cleaning of pulsed beam in an ytterbium doped multimode fiber
2017
International audience; We experimentally demonstrate that Kerr spatial self-cleaning of a pulsed beam can be obtained in an amplifying multimode optical fiber. An input peak power of 500 W only was sufficient to produce a quasi-single-mode emission from the double-clad ytterbium doped multimode fiber (YMMF) with non-parabolic refractive index profile. We compare the self-cleaning behavior observed in the same fiber with loss and with gain. Laser gain introduces new opportunities to achieve spatial self-cleaning of light in multimode fibers at a relatively low power threshold.
Coexistence of quasi-CW and SBS-boosted selfQ-switched pulsing in ytterbium-doped fiber laser with low Q-factor cavity
2020
We report the results of an experimental study of an ytterbium-doped fiber laser with low Q-factor cavity. We demonstrate that the laser operates in two randomly alternating sub-regimes, quasi-CW (QCW) and self-Q-switching (SQS), the latter ignited by stimulated Brillouin scattering (SBS). We show that probability of each sub-regime depends on pump power: QCW dominates slightly above the laser threshold while SQS pulsing prevails at higher pump powers. We also discuss the featuring details of QCW sub-regime and its role in instabilities (jittering) of SBS-boosted SQS pulsing as well as the statistical properties of the latter.
Experimental demonstration of 160-GHz densely dispersion-managed soliton transmission in a single channel over 896 km of commercial fibers
2003
International audience; We experimentally demonstrate the first 160-GHz densely dispersion-managed soliton transmission in a single channel at 1550 nm over nearly 900 km using commercially available non-zero dispersion-shifted fibers. This performance has been achieved by using a 16 km-long recirculating loop configuration and an appropriate design of the dispersion map.
Stimulated Brillouin scattering in Germanium-doped-core optical fibers up to 98% mol doping level
2018
International audience; We experimentally investigate stimulated Brillouin scattering in several highly GeO2-doped optical fibers and report wide frequency tunability over more than 3 GHz and Brillouin gain 7 times larger than in standard silica fibers.
Demonstration of polarization pulling in a fiber-optical parametric amplifier
2012
International audience; We report the experimental demonstration of all-optical polarization pulling of an initially polarization-scrambled signal using a fiber-optical parametric amplifier. Nonlinear polarization pulling has been achieved for both the signal and idler with 25 dB gain.
Ultra-high repetition all optical picosecond pulsed sources : applications in optical telecommunications
2013
This thesis presents the work carried out on the realization of fibered 40-GHz picosecond optical pulse sources in the telecommunications C-band. In the first part, we present a numerical and experimental study of the generation of 40-GHz pulse trains thanks to the nonlinear compression of an initial beat-signal by multiple Four-Wave Mixing process. Enhanced temporal stability is achieved by generating the sinusoidal beating thanks to a Mach-Zehnder modulator driven at its zero-transmission working point. In order to improve the quality of the generated pulses, we also demonstrate the suppression of stimulated Brillouin back-scattering by inserting several optical isolators into the compres…
Active photonic crystals based on surface acoustic waves
2003
An active photonic crystal (PC) based on the modulation of a one-dimensional cavity resonator by electrically-generated surface acoustic waves is described. The high nonthermal population of surface modes combined with the enhanced Brillouin scattering in the cavity increases the intensity of the scattered light to values comparable to the excitation intensity. This process is employed to switch and modulate light beams in PCs.
Efficient interrogation method of forward Brillouin scattering in optical fibers using a narrow bandwidth long-period grating
2020
A new technique, to the best of our knowledge, for the characterization of the effective refractive index modulation in optical fibers due to transverse acoustic mode resonances excited by electrostriction is reported. The resonances excited by an optical pulse are probed by a narrow bandwidth long-period grating (LPG) inscribed in the fiber, which is interrogated by a continuous wave (CW) beam. The LPG used in this experiment has a narrow bandwidth and high sensitivity to small mode index perturbations, allowing the measurement of index variations from below 10 − 9 to 10 − 6 . Radial and torsional-radial acoustic modes were characterized up to 1.1 GHz. The linewidth of resonances was found…