Widely Tunable, Low Linewidth, and High Power Laser Source using an Electro-Optic Comb and Injection-Locked Slave Laser Array

We propose a simple approach to implement a tunable, high power and narrow linewidth laser source based on a series of highly coherent tones from an electro-optic frequency comb and a set of 3 DFB slave lasers. We experimentally demonstrate approximately 1.25 THz (10 nm) of tuning within the C-Band centered at 192.9 THz (1555 nm). The output power is approximately 100 mW (20 dBm), with a side band suppression ratio greater than 55 dB, and a linewidth below 400 Hz across the full range of tunability. This approach is scalable and may be extended to cover a significantly broader optical spectral range

Spatio-temporal characterization of the electric field of breathers in an optical fiber

International audienc

Full-field characterization of breather dynamics over the whole length of an optical fiber

International audienceFull-field longitudinal characterization of picosecond pulse train formation in optical fibers is reported. The spatio-temporal evolution is obtained via fast and non-invasive distributed measurements in phase and intensity of the main spectral components of the pulses. To illustrate the performance of the setup, we report the first time-domain experimental observation of the symmetry breaking of Fermi-Pasta-Ulam recurrences. Experimental results are in good agreement with numerical simulations

Phase and power experimental study of seeded modulation instability in passive fiber ring cavities

International audienc

Experimental validation in optical fibers of multiple Fermi-Pasta-Ulam-Tsingou recurrences theory

International audienc

Waveguide tapering for improved parametric amplification in integrated nonlinear Si3N4 waveguides

In this paper, we propose and numerically investigate waveguide tapering to improve optical parametric amplification in integrated nonlinear Si3N4 circuits. The phase matching condition of parametric amplification changes along the length of uniform Si3N4 waveguides, due to the non-negligible propagation loss, potentially causing peak-gain wavelength shifts of more than 20 nm. By tapering the waveguide width along propagation, we can achieve a 2.5 dB higher maximum parametric gain thanks to the improved phase matching, which can also broaden the amplification bandwidth. Therefore, the length of an optimally tapered Si3N4 waveguide can be 23% shorter than a uniform one in the case of a 3.0 dB/m propagation loss and a single continuous-wavelength pump. Quasi-continuous tapers are efficient to approximate continuous ones and might simplify the fabrication of long tapered nonlinear Si3N4 waveguides, which are promising for optical signal processing and optical communications

Instabilité de modulation et récurrences de Fermi-Pasta-Ulam-Tsingou dans les fibres optiques

Ce travail porte sur l’étude du processus d’instabilité de modulation dans les fibres optiques et notamment son étape nonlinéraire. Ce processus peut induire une dynamique complexe de couplage entre une onde de pompe et des bandes latérales avec notamment un, voire de multiples, retour à l’état initial s’il est amorcé activement. Ce phénomène est connu sous le nom de récurrences de Fermi-Pasta-Ulam-Tsingou. Dans cette thèse, nous décrivons la mise en place d’un montage expérimental se basant sur la détection hétérodyne d’un signal rétrodiffusé et une compensation active des pertes. Il permet une caractérisation distribuée rapide et non-invasive tout le long d’une fibre de l’amplitude et la phase des principales composantes spectrales d’une impulsion. En outre, nous détaillons une méthode de post-traitement qui nous permet de retrouver l’évolution du champ complexe dans le domaine temporel. Mettant en oeuvre ces outils, nous avons rapporté l’observation de deux récurrences de Fermi-Padta-Ulam-Tsingou et leur brisure de symétrie, à la fois dans les domaines fréquentiel et temporel. Suite à cela, nous avons quantitativement examiné l’influence des conditions initiales des trois ondes envoyées dans la fibre sur la position des récurrences, en comparaison avec de récentes prédictions théoriques. Finalement, nous avons étudié la dynamique de structures nonlinéraies d’ordre supérieur, à savoir les breathers du deuxième ordre.This work deals with the investigation of the modulation instability process in optical fibres and in particular its nonlinear stage. This process can induce a complex coupling dynamic between the pump and sidebands waves, with a single or multiple returns to the initial state if it is seeded. This phenomenon is referred as Fermi-Pasta-Ulam-Tsingou recurrences. In this thesis, we describe the implementation of a novel experimental technique based on heterodyne optical time-domain reflectometry and active compensation of losses. It allows fast and non-invasive distributed characterisation along a fibre of the amplitude and phase of the main frequency components of a pulse. Furthermore, we detail a simple post-processing method which enable us to retrieve the complex field evolution in the time domain. Using these tools, we reported the observation of two Fermi-Pasta-Ulam-Tsingou recurrences and their symmetry-breaking nature, both in the frequency and time domain. Then, we quantitatively studied the influence of the initial three-wave input conditions on the recurrence positions, in regards with recent theoretical predictions. Finally, we investigated the dynamics of higher-order nonlinear structures, namely second-order breathers

Widely tunable, low linewidth, and high power laser source using an electro-optic comb and injection-locked slave laser array

We propose and implement a tunable, high power and narrow linewidth laser source based on a series of highly coherent tones from an electro-optic frequency comb and a set of 3 DFB slave lasers. We experimentally demonstrate approximately 1.25 THz (10 nm) of tuning within the C-Band centered at 192.9 THz (1555 nm). The output power is approximately 100 mW (20 dBm), with a side band suppression ratio greater than 55 dB and a linewidth below 400 Hz across the full range of tunability. This approach is scalable and may be extended to cover a significantly broader optical spectral range.</jats:p

Phase-sensitive seeded modulation instability in passive fiber resonators

Modulation instability is one of the most ubiquitous phenomena in physics. Here we investigate the phase-sensitive properties of modulation instability with harmonic seeding in passive fiber resonators. Theoretical investigations based on the Lugiato−Lefever equation with time dependent pump and a three-wave truncation show that the dynamics of the system is sensitive to the relative phase between input signal, idler, and pump waves. The modulation instability gain can even vanish for a peculiar value of the initial relative phase. An advanced multi-heterodyne measurement technique had been developed to record the real time evolution, round-trip to round-trip, of the power and phase of the output cavity field to confirm these theoretical predictions