Showing papers by "Guy Millot published in 2018"
TL;DR: In this article, the authors investigated the rogue wave dynamics governed by coupled nonlinear Schrodinger equation (NLSE) models and reported the evidence of a group of three dark rogue waves, the so-called dark three-sister rogue waves.
Abstract: Over the past decade, the rogue wave debate has stimulated the comparison of predictions and observations among different branches of wave physics, particularly between hydrodynamics and optics, in situations where analogous dynamical behaviors can be identified, thanks to the use of common universal models. Although the scalar nonlinear Schr\"odinger equation (NLSE) has constantly played a central role for rogue wave investigations, moving beyond the standard NLSE model is relevant and needful for describing more general classes of physical systems and applications. In this direction, the coupled NLSEs are known to play a pivotal role for the understanding of the complex wave dynamics in hydrodynamics and optics. Benefiting from the advanced technology of high-speed telecommunication-grade components, and relying on a careful design of the nonlinear propagation of orthogonally polarized optical pump waves in a randomly birefringent telecom fiber, this work explores, both theoretically and experimentally, the rogue wave dynamics governed by such coupled NLSEs. We report, for the first time, the evidence of a group of three dark rogue waves, the so-called dark three-sister rogue waves, where experiments, numerics, and analytics show a very good consistency.
76 citations
TL;DR: In this article, the authors demonstrate simultaneous spatial and temporal compression in the propagation of light pulses in multimode nonlinear optical fibers and reveal that the spatial beam self-cleaning recently discovered in graded-index multimode fibers is accompanied by significant temporal reshaping and up to fourfold shortening of the injected subnanosecond laser pulses.
Abstract: We experimentally demonstrate simultaneous spatial and temporal compression in the propagation of light pulses in multimode nonlinear optical fibers. We reveal that the spatial beam self-cleaning recently discovered in graded-index multimode fibers is accompanied by significant temporal reshaping and up to fourfold shortening of the injected subnanosecond laser pulses. Since the nonlinear coupling among the modes strongly depends on the instantaneous power, we explore the entire range of the nonlinear dynamics with a single optical pulse, where the optical power is continuously varied across the pulse profile.
50 citations
TL;DR: In this paper, a stable and wavelength tunable all-fibered dual-comb spectrometer operating in the 2'μm region was developed for CO2 absorption spectra over 37'nm.
Abstract: Mid-infrared dual-comb spectroscopy offers interesting applications since molecules have their strongest rotational–vibrational absorptions in this frequency domain. Besides, generating frequency combs with electro-optic modulators recently showed promising results toward dual-comb spectroscopy. Here, we report a conversion in the mid-infrared of two mutually coherent frequency combs generated with electro-optic modulators to perform dual-comb spectroscopy in this region. Using fourth-order modulation instability taking place in the normal dispersion regime of a highly nonlinear fiber and by seeding this phenomenon with a frequency agile and low-power laser around 1.3 μm, we develop a stable and wavelength tunable all-fibered dual-comb spectrometer operating in the 2 μm region. This allows us to investigate CO2 absorption spectra over 37 nm and to measure collisional broadening coefficients of a few rotational–vibrational lines. Frequency combs correspond to optical spectra composed of a succession of equally spaced lines that can be used in numerous fields such as high-precision spectroscopy. The authors report a new way of converting frequency combs in the mid-infrared region, which has potential applications in molecular spectroscopy and gas sensing.
29 citations
TL;DR: In this paper, the competition between Kerr beam self-cleaning and Raman beam cleanup in a multimode air-silica microstructure optical fiber was studied for a certain range of input powers only.
Abstract: We experimentally study the competition between Kerr beam self-cleaning and Raman beam cleanup in a multimode air-silica microstructure optical fiber. Kerr beam self-cleaning of the pump is observed for a certain range of input powers only. Stokes Raman beam generation and cleanup lead to both depletion and degradation of beam quality for the pump. The interplay of modal four-wave mixing and Raman scattering in the infrared domain leads to the generation of a multimode supercontinuum ranging from 500 nm up to 1800 nm.
28 citations
TL;DR: In this paper, the process of seeded intermodal four-wave mixing in a graded-index multimode fiber, pumped in the normal dispersion regime, is investigated and a detailed characterization of the spectral and spatial properties of these sidebands shows good agreement with theoretical predictions from phase-matching conditions.
Abstract: 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-μm 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 sidebands shows good agreement with theoretical predictions from the phase-matching conditions. Interestingly, we demonstrate that both the second- and fourth-order dispersions must be included in the phase-matching conditions to get better agreement with experimental measurements. Furthermore, temporal measurements performed with a fast photodiode reveal the generation of multiple pulse structures.
27 citations
Posted Content•
TL;DR: In this paper, the authors report the experimental observation of Kerr beam self-cleaning in a graded-index multimode fiber, leading to output beam profiles different from a bell shape, close to the $LP_{01}$ mode.
Abstract: We report the experimental observation of Kerr beam self-cleaning in a graded-index multimode fiber, leading to output beam profiles different from a bell shape, close to the $LP_{01}$ mode. For specific coupling conditions, nonlinear coupling among the guided modes can reshape the output speckle pattern generated by a pulsed beam into the low order $LP_{11}$ mode. This was observed in a few meters long multimode fiber with 750 ps pulses at 1064 nm in the normal dispersion regime. The power threshold for $LP_{11}$ mode self-cleaning was about three times larger than that required for Kerr nonlinear self- cleaning into the $LP_{01}$ mode.
16 citations
TL;DR: In this article, the competition between Kerr beam self-cleaning and Raman beam cleanup in a multimode air-silica microstructure optical fiber was studied for a certain range of input powers only.
Abstract: We experimentally study the competition between Kerr beam self-cleaning and Raman beam cleanup in a multimode air-silica microstructure optical fiber. Kerr beam self-cleaning of the pump is observed for a certain range of input powers only. Raman Stokes beam generation and cleanup lead to both depletion and degradation of beam quality for the pump. The interplay of modal four-wave mixing and Raman scattering in the infrared domain lead to the generation of a multimode supercontinuum ranging from 500 nm up to 1800 nm.
15 citations
TL;DR: In this article, single mode Si waveguides efficiently sustain high-speed transmissions at 2 εm with a power penalty below 1 dB, and the same waveguide structure with a conversion window over 70 nm and an efficiency as high as 25 dB that can be further increased in the pulsed pump regime.
Abstract: We show that single mode Si waveguides efficiently sustain high-speed transmissions at 2 $\mu$m. We report the transmission of a 10 Gbit/s signal over 7 cm with a power penalty below 1 dB. Parametric conversion in the continuous wave regime is also demonstrated using the same waveguide structure with a conversion window over 70 nm and an efficiency as high as-25 dB that can be further increased in the pulsed pump regime.
13 citations
TL;DR: In this paper, the polarization dynamics of Kerr beam self-cleaning in a graded-index multimode optical fiber were investigated and it was shown that spatial beam cleaning is accompanied by nonlinear polarization rotation and a substantial increase of the degree of linear polarization.
Abstract: We experimentally study polarization dynamics of Kerr beam self-cleaning in a graded-index multimode optical fiber. We show that spatial beam cleaning is accompanied by nonlinear polarization rotation, and a substantial increase of the degree of linear polarization.
11 citations
14 May 2018
TL;DR: In this article, the authors demonstrate broadband supercontinuum generation from 560 nm up to 2350 nm by coupling a Q-switched picosecond microchip laser at 1064 nm into a 15 μm-core step-index germanium-doped silica fiber.
Abstract: We demonstrate broadband supercontinuum generation from 560 nm up to 2350 nm by coupling a Q-switched picosecond microchip laser at 1064 nm into a 15 μm-core step-index germanium-doped silica fiber, designed to support five spatial modes at 1064 nm. It is further shown that multiple cascaded intermodal four-wave mixing and Raman processes take place in the fiber with large frequency detuning up to 150 THz. The multimode properties of this fiber yield a number of intermodal nonlinear coupling terms and the parametric sideband wavelengths have been obtained from the phasematching condition for intermodal four-wave mixing.
6 citations
TL;DR: The asymmetrically phase-detuned dual pumping of a passive inhomogeneous fiber ring cavity is investigated and multicomb states at offset frequencies can be selectively generated by means of the mismatch parameter and the coexistence of Turing and Faraday instabilities.
Abstract: We numerically and experimentally investigate the asymmetrically phase-detuned dual pumping of a passive inhomogeneous fiber ring cavity. This configuration originates from the fine control of frequency mismatch between the frequency spacing of the bichromatic pump and the free spectral range of the cavity. Multicomb states at offset frequencies can be selectively generated by means of the mismatch parameter and the coexistence of Turing and Faraday instabilities.
26 Jan 2018
TL;DR: In this paper, the authors overview recent advances in spatiotemporal beam shaping in nonlinear multimode optical fibers, including the Kerr-induced beam self-cleaning, which redistributes most of the beam energy into a robust bell-shaped beam close to the fundamental mode.
Abstract: We overview recent advances in the research on spatiotemporal beam shaping in nonlinear multimode optical fibers. An intense light beam coupled to a graded index (GRIN) highly multimode fiber undergoes a series of complex nonlinear processes when its power grows larger. Among them, the lowest threshold effect is the Kerr-induced beam self-cleaning, that redistributes most of the beam energy into a robust bell-shaped beam close to the fundamental mode. At higher powers a series of spectral sidebands is generated, thanks to the phase matching induced by the long period grating due to the periodic self-imaging of the beam and the Kerr effect. Subsequently a broadband and spectrally flat supercontinuum is generated, extending from the visible to the mid-infrared.
TL;DR: In this article, the authors overview recent advances in spatiotemporal beam shaping in nonlinear multimode optical fibers, including the Kerr-induced beam self-cleaning, which redistributes most of the beam energy into a robust bell-shaped beam close to the fundamental mode.
Abstract: We overview recent advances in the research on spatiotemporal beam shaping in nonlinear multimode optical fibers. An intense light beam coupled to a graded index (GRIN) highly multimode fiber undergoes a series of complex nonlinear processes when its power grows larger. Among them, the lowest threshold effect is the Kerr-induced beam self-cleaning, that redistributes most of the beam energy into a robust bell-shaped beam close to the fundamental mode. At higher powers a series of spectral sidebands is generated, thanks to the phase matching induced by the long period grating due to the periodic self-imaging of the beam and the Kerr effect. Subsequently a broadband and spectrally flat supercontinuum is generated, extending from the visible to the mid-infrared.
Posted Content•
TL;DR: In this paper, the authors demonstrate Kerr beam self-cleaning in the anomalous dispersion regime of graded-index multimode optical fibers, using 90 ps duration, highly chirped (2 nm bandwidth at -3dB) optical pulses at 1562 nm.
Abstract: We experimentally demonstrate Kerr beam self-cleaning in the anomalous dispersion regime of graded-index multimode optical fibers. By using 90 ps duration, highly chirped (2 nm bandwidth at -3dB) optical pulses at 1562 nm, we demonstrate a 2 decades reduction, with respect to previous experiments in the normal dispersion regime, of threshold peak power for beam self-cleaning into the fundamental mode of the fiber, accompanied by more than 65% nonlinear increase of intensity correlation into the fundamental mode. Highly efficient self-selection of the LP11 mode is also observed. Self-cleaned beams remain spatio-temporally stable for more than a decade of variation of the peak pulse power.
Posted Content•
TL;DR: In this paper, the authors report the experimental observation of Kerr nonlinear beam auto-selection in a graded-index multimode fiber, leading to output beam profiles different from a bell shape.
Abstract: We report the experimental observation of Kerr nonlinear beam auto-selection in a graded-index multimode fiber, leading to output beam profiles different from a bell shape. For specific coupling conditions, multiple four-wave mixing among the guided modes may reshape the output speckle pattern generated by a pulsed beam into a low order mode (LP11 or LP21). This was observed in a few meters long multimode fiber with either 750 ps or 7 ps pulses at 1064 nm in the normal dispersion regime. The power threshold for low-order mode auto- selection was about three times larger than that required for Kerr nonlinear self-cleaning into a bell-shaped beam.
02 Jul 2018
TL;DR: In this article, the transmission of a 10 Gbps telecommunication signal at 2 μm in waveguides made of three different materials: Si, SiGe and TiO2 was reported.
Abstract: We report the transmission of a 10 Gbps telecommunication signal at 2 μm in waveguides made of three different materials: Si, SiGe and TiO2. Bit error rates below 10−9 can be achieved after transmission in the devices with subwavelength dimensions.
Posted Content•
TL;DR: In this article, the authors experimentally and numerically report on the formation of ballistic dispersive shock waves that mimic superfluid behavior in optical fibers, triggered by a strong nonlinear phase shift induced by a high power pump pulse on a cross-polarized continuous-wave probe field, and exhibit a central void surrounded by two oscillating fronts moving away from each other with opposite velocities.
Abstract: We experimentally and numerically report on the formation of ballistic dispersive shock waves that mimic superfluid behavior in optical fibers. The shock wave is triggered by a strong nonlinear phase shift induced by a high power pump pulse on a cross-polarized continuous-wave probe field, and it exhibits a central void surrounded by two oscillating fronts moving away from each other with opposite velocities. The impact of disorder in the continuous-wave background as well as the difference of group-velocities between the two orthogonally polarized waves is also investigated. Our experimental observations are in very good agreement with theoretical and numerical predictions derived from the Manakov model.
12 Nov 2018
TL;DR: In this article, step-index few-mode fibers are combined with a simple microchip picosecond laser to give a multi-octave spanning supercontinuum output by cascaded Raman scattering and intermodal FWM.
Abstract: 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.
04 Jun 2018
TL;DR: In this article, the authors investigated complex temporal pulse reshaping that accompanies Kerr beam self-cleaning in multimode optical fibers and also studied the output beam shape dependence on initial conditions.
Abstract: We experimentally and theoretically investigate complex temporal pulse reshaping that accompanies Kerr beam self-cleaning in multimode optical fibers. We also study the output beam shape dependence on initial conditions.
02 Jul 2018
TL;DR: In this paper, the dynamics of the Kerr self-cleaning effect in a GRIN multimode fiber were investigated at high power and characterized, thus enriching the dynamics for quasi fundamental mode generation.
Abstract: Modal attraction towards low order modes in a GRIN multimode fiber was experimentally observed at high power and characterized, thus enriching the dynamics of the Kerr self-cleaning effect leading to quasi fundamental mode generation.
13 May 2018
TL;DR: In this article, the interplay of modal four-wave mixing and Raman scattering leads to high-brightness multimode supercontinuum, and the authors experimentally study the impact of Kerr and Rambusan beam cleanup in multimode air-silica microstructure optical fiber.
Abstract: We experimentally study the interplay of Kerr and Raman beam cleanup in multimode air-silica microstructure optical fiber. The interplay of modal four-wave mixing and Raman scattering leads to high-brightness multimode supercontinuum.
02 Jul 2018
TL;DR: In this article, the authors explore the complex nonlinear dynamics with a single long pulse, where the optical power is continuously varied across its profile, and explore the nonlinear self-cleaning in graded-index multimode fibers with power-dependent temporal pulse reshaping.
Abstract: Kerr beam self-cleaning in graded-index multimode fibers is accompanied by power-dependent temporal pulse reshaping. We explore the complex nonlinear dynamics with a single long pulse, where the optical power is continuously varied across its profile.
01 Jan 2018
TL;DR: In this paper, the polarization dynamics of Kerr beam self-cleaning in a graded-index multimode optical fiber were investigated and it was shown that spatial beam cleaning is accompanied by nonlinear polarization rotation and a substantial increase of the degree of linear polarization.
Abstract: We experimentally study polarization dynamics of Kerr beam self-cleaning in a graded-index multimode optical fiber. We show that spatial beam cleaning is accompanied by nonlinear polarization rotation, and a substantial increase of the degree of linear polarization.
13 May 2018
TL;DR: In this paper, the authors overview recent advances in the nonlinear optics of multimode optical fibers, including ultrabroadband sideband and supercontinuum generation, Kerr and Raman beam cleanup, modal modulation instabilities, four wave mixing, and second harmonic beam cleaning.
Abstract: We overview recent advances in the nonlinear optics of multimode optical fibers, including ultrabroadband sideband and supercontinuum generation, Kerr and Raman beam cleanup, modal modulation instabilities, four wave mixing, and second harmonic beam cleaning.
13 May 2018
TL;DR: By controlling pump modes injected in the normal dispersion regime of few-mode graded index optical fiber, the authors investigated intermodal noise-seeded modulation instability and generation of highly-detuned cascaded inter-modal four-wave mixing sidebands.
Abstract: By controlling pump modes injected in the normal dispersion regime of few-mode graded index optical fiber, we investigated intermodal noise-seeded modulation instability and generation of highly-detuned cascaded intermodal four-wave mixing sidebands.
03 Jul 2018
TL;DR: HAL as discussed by the authors is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not, which may come from teaching and research institutions in France or abroad, or from public or private research centers.
Abstract: HAL is a multi-disciplinary open access archive for the deposit and dissemination of scientific research documents, whether they are published or not. The documents may come from teaching and research institutions in France or abroad, or from public or private research centers. L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires publics ou privés. Génération de supercontinuum par cascade de mélanges à quatre ondes intermodaux dans une fibre optique multimode à saut d’indice S Perret, G. Fanjoux, L. Bigot, J. Fatome, G. Millot, J Dudley, Thibaut Sylvestre