Demonstration of polarization pulling in a fiber-optical parametric amplifier

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.

Génération de supercontinuum par cascade de mélanges à quatre ondes intermodaux dans une fibre optique multimode à saut d'indice

International audience

Real Time Measurements of Spectral Instabilities in Ultrafast Fibre Laser Systems

International audience;

Generation of vector dark-soliton trains by induced modulational instability in a highly birefringent fiber

International audience; We present a set of experimental observations that demonstrate the generation of vector trains of dark-soliton pulses in the orthogonal axes of a highly birefringent optical fiber. We generated dark-soliton trains with terahertz repetition rate in the normal group-velocity dispersion regime by inducing a polarization modulational instability by mixing two intense, orthogonal continuous laser beams. Numerical solutions of the propagation equations were used to optimize the emission of vector dark pulses at the fiber output.

Amplification paramétrique d'impulsion ultra-courte dans les fibres optiques

International audience;

Demonstration of Stimulated-Raman-scattering suppression in optical fibers in a multifrequency pumping configuration

International audience; We analyze the stimulated-Raman-scattering-(SRS) process induced by a linearly polarized multifrequency pump field in a normally dispersive single-mode fiber. We show, by theoretical analysis and numerical simulations, that the SRS process may be either controlled by switching all the generated Stokes radiations to the lowest-frequency pump or suppressed for all the frequency components of the pump field. The suppression process is achieved by an appropriate choice of the frequency separation between the pumps and a particular power distribution among the frequency components of the pump field. We present experimental spectra showing the effectiveness of this suppres…

Real-time measurement of soliton-similariton explosions and intermittence instabilities in a mode-locked fibre laser

International audience; Ultrafast mode-locked lasers are well-known to display a rich variety of unstable dissipative soliton dynamics resulting from the interplay of nonlinearity, dispersion and dissipation. Although laser instabilities have been known and studied in depth for many years, their properties have recently received greatly renewed attention because of the development of time and frequency domain techniques that allow laser dynamics and instabilities to be measured in real-time. This has allowed the variations in circulating pulse characteristics to be examined on a roundtrip to roundtrip basis, providing a new window into understanding these instabilities and how they develop …

Suppression of stimulated Raman scattering in optical fibres by power-controlled multifrequency pumping

International audience; We present a method for suppressing the stimulated Raman scattering process induced by a multifrequency pump field propagating in a normally dispersive single-mode fibre. The suppression process is completely achieved by suitably choosing the frequency separation between the pumps, as well as the power distribution among the frequency components of the pump field. The experimental spectra show the effectiveness of this suppression process for a dual-frequency pumping configuration.

Seeded intermodal four-wave mixing in a highly multimode fiber

International audience; We experimentally and theoretically investigate the process of seeded intermodal four-wave mixing in a graded-index multimode fiber, pumped in the normal dispersion regime. By using a fiber with a 100-mu m core diameter, we generate a parametric sideband in the C-band (1530-1565 nm), hence allowing the use of an erbium-based laser to seed the mixing process. To limit nonlinear coupling between the pump and the seed to low-order fiber modes, the waist diameter of the pump beam is properly adjusted. We observe that the superimposed seed stimulates the generation of new spectral sidebands. A detailed characterization of the spectral and spatial properties of these sideb…

Laser impulsionnel Raman à verrouillage de modes passif fonctionnant à 1 GHz

National audience

Observation of elastic anisotropy in strained optical nanofibers using Brillouin spectroscopy

Optical nanofibers (ONFs) are excellent nanophotonic platforms for many applications such as optical sensing, quantum photonics, and nonlinear optics, due to both tight optical confinement and their evanescent field. From an acoustic viewpoint, it has recently been reported the observation of a new class of Brillouin acoustic resonances in optical nanofibers, including hybrid shear/longitudinal acoustic waves (HAWs) and surface acoustic waves (SAWs) [1–2]. It has been later shown that, under axial tensile strain, the Brillouin frequency shifts (BFS) of these elastic resonances are fundamentally different from that of standard optical fibers [3]. This is principally due to the hybrid nature …

A Brillouin fiber laser at 2 µm based on a step-index tellurite (TeO2) optical fiber

International audience; We demonstrate Brillouin lasing at 2-µm using a step-index Tellurite-glass optical fiber in a passive fiber ring cavity. A low lasing threshold of 70 mW was achieved with a Brillouin gain of 1.05 × 10-10 m/W for a Brillouin frequency shift of 6.165 GHz. Stimulated Brillouin scattering (SBS) in optical fibers is a nonlinear process with important applications such as distributed optical fiber sensing, microwave photonics, optical storage, and fiber lasers. The latter application has attracted significant interest as highly coherent laser sources with sub-Hz linewidth can be achieved using SBS in optical cavities. To date, most of Brillouin fibers lasers (BFLs) have be…

Wavelength conversion from 1.3 µm to 1.5 µm in single-mode optical fibres using Raman-assisted three-wave mixing

International audience; We theoretically analyse the achievement of wide-range all-optical wavelength conversion of a 1.31 µm signal to an idler wave in the 1.5 µm spectral region by Raman-assisted three-wave mixing in single-mode optical fibres. Raman-assisted three-wave mixing allows efficient conversion on a large frequency detuning bandwidth while alleviating the need for stringent phase-matching conditions.

Demonstration of polarization pulling using a fiber-optic parametric amplifier

International audience; We report the observation of all-optical polarization pulling of an initially polarization-scrambled signal using parametric amplification in a highly nonlinear optical fiber. Broadband polarization pulling has been achieved both for the signal and idler waves with up to 25 dB gain using the strong polarization sensitivity of parametric amplifiers. We further derive the probability distribution function for the final polarization state, assuming a randomly polarized initial state, and we show that it agrees well with the experiments.

Shaping Brillouin Light in Specialty Optical Fibers

High-harmonic km-long self-pulsed Raman fiber laser

Raman all-fiber lasers have attracted considerable interest during the past two decades due to their convenient use and extended wavelength coverage when compared to rare-earth-doped fiber lasers. Still, little is known about their potential as pulsed laser sources. Mode locked Raman fiber lasers have been demonstrated quite recently [1,2], as well as harmonic mode-locking with a record of 500,000 intra-cavity pulses in a dissipative four-wave mixing configuration using a fiber Bragg grating [3].

Supercontinuum Generation and Intermodal Four-Wave Mixing in a Step-Index Few-Mode Fibre

International audience; The complex spatiotemporal dynamics of nonlinear light propagation in multimode fibers (MMFs) has recently witnessed a renewed interest because of their experimental realization in emerging key areas of laser physics and fiber optics [1]. Specifically, MMFs have a number of linear and nonlinear optical properties that make them very attractive to investigate new spatiotemporal effects fundamentally different from standard single-mode fibers. These include the observation of multimode solitons [2], intermodal four-wave mixing (FWM) [3], geometric parametric instabilities [4], spatial beam self-cleaning [5], and the generation of supercontinuum (SC) light when pumping …

CONVERSIONS DE FREQUENCE ULTRA LARGE BANDE PAR MELANGE A QUATRE ONDES INTERMODAL EN CASCADE DANS LES FIBRES MULTIMODES

International audience; Nous mettons en évidence des effets de conversion spectrale paramétrique avec des décalages spectraux très importants (~200THz) dans une fibre à gradient d'indice qui, pompée avec une source laser picoseconde à 1064nm, supporte quatre modes de propagation. À travers des études expérimentales, analytiques et numériques détaillées, nous montrons que les multiples raies paramétriques sont générées par un processus en cascade complexe faisant intervenir des mélanges à quatre ondes intermodaux. Les longueurs d'onde paramétriques résultantes s'étendent dans le visible jusqu'à 410nm et dans le proche infrarouge jusqu'à 1355nm. MOTS-CLEFS : dynamique spatio-temporelle ; conv…

Génération de supercontinuum par cascade de mélanges à quatre ondes intermodaux dans une fibre optique multimode à saut d'indice

International audience

Fiber optical parametric polarizer

In this work, a fiber-optical parametric polarizer (FOPP), i.e., a polarizing device based on parametric amplification in optical fibers is demonstrated. This was achieved for both the signal and idler waves with 25 dB gain over a broad bandwidth using the strong polarization-dependent gain (PDG) of parametric amplifiers. The experimental values of the degree of polarization (DOP) calculated from the Stokes parameters are indicated above each sphere. The gain spectra are also plotted with the parametric gain and the signal OSNR in insets. The Poincare sphere represents the three normalized Stokes parameters (S1,S2,S3) in unit radius. Results show that he DOP of the signal significantly incr…

Cascaded intermodal four-wave mixing in a few-mode fiber

During the last few years, intensive works on multimode fibers allowed for the observation of a series of complex and novel nonlinear spatiotemporal phenomena such as: multimode solitons, geometric parametric instability, supercontinuum generation, and self-induced beam cleaning [1-4]. Among these phenomena, intermodal four-wave mixing (IMFWM) demonstrated larger frequency shifts in comparison with single-mode fibers. In this work, we studied IMFWM in a few-mode graded-index fiber (GRIN-FMF) pumped in the normal dispersion regime at 1064 nm. We report parametric sidebands detuned by hundreds of THz from the pump.

Real-time measurements of spontaneous breathers and rogue wave events in optical fibre modulation instability

Modulation instability is a fundamental process of nonlinear science, leading to the unstable breakup of a constant amplitude solution of a physical system. There has been particular interest in studying modulation instability in the cubic nonlinear Schrödinger equation, a generic model for a host of nonlinear systems including superfluids, fibre optics, plasmas and Bose–Einstein condensates. Modulation instability is also a significant area of study in the context of understanding the emergence of high amplitude events that satisfy rogue wave statistical criteria. Here, exploiting advances in ultrafast optical metrology, we perform real-time measurements in an optical fibre system of the u…

Raman-assisted three-wave mixing of non-phase-matched waves in optical fibres: application to wide-range frequency conversion

International audience; We analyse theoretically and experimentally the Raman-assisted parametric coupling between non-phase-matched waves propagating in normally dispersive single-mode fibres. We perform a careful analysis of the wave-coupling behaviour, which shows that scalar and vector three-wave mixing (TWM) interactions induce a relatively small periodic power flow between a central-frequency pump at frequency ω0 and a pair of up-shifted (anti-Stokes) and down-shifted (Stokes) sidebands at frequencies View the MathML source and View the MathML source, respectively. For sufficiently high pump powers, the stimulated Raman scattering enters into play, causing a unilateral transfer of ene…

Raman-assisted parametric frequency conversion in a normally dispersive single-mode fiber

International audience; We demonstrate efficient frequency conversion with large frequency shifts of an anti-Stokes signal into a parametrically seeded Stokes idler, which is generated by a highly mismatched three-wave mixing interaction and subsequent Raman amplification in a normally dispersive single-mode fiber. The use of non-phase-matched waves in Raman-assisted three-wave mixing interactions overcomes the strict spectral limitations imposed by phase-matching conditions in parametric frequency-conversion processes.

Supercontinuum generation by cascaded intermodal Raman and FWM processes in step-index few-mode fibers

International audience; This work shows that step-index few-mode fibers can be combined with a simple microchip picosecond laser to give a multi-octave spanning supercontinuum output by cascaded Raman scattering and intermodal FWM.

Stimulated Brillouin scattering in Germanium-doped-core optical fibers up to 98% mol doping level

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.