Search results for "LEAN"
showing 10 items of 3611 documents
Single-mode room-temperature emission with a silicon rod lattice
2006
The authors experimentally evidence an increase of light emission efficiency at room temperature in a silicon-on-insulator photonic crystal. The photonic crystal is made of a triangular lattice of silicon rods and operates as a single-mode light extractor. It exhibits a luminescence intensity two orders of magnitude higher than silicon-on-insulator substrate. In light of photoluminescence experiments, emission diagram measurements, and finite difference time domain calculations, they identify the different optical properties of the photonic crystal and they demonstrate the existence of at least a fivefold emission efficiency enhancement per surface unit.
Coupled experiment/simulation approach for the design of radiation-hardened rare-earth doped optical fibers and amplifiers
2011
We developed an approach to design radiation-hardened rare earth -doped fibers and amplifiers. This methodology combines testing experiments on these devices with particle swarm optimization (PSO) calculations. The composition of Er/Yb-doped phosphosilicate fibers was improved by introducing Cerium inside their cores. Such composition strongly reduces the amplifier radiation sensitivity, limiting its degradation: we observed a gain decreasing from 19 dB to 18 dB after 50 krad whereas previous studies reported higher degradations up to 0°dB at such doses. PSO calculations, taking only into account the radiation effects on the absorption efficiency around the pump and emission wavelengths, co…
New fiber laser architecture with transform-limited nonlinear spectral compression
2012
International audience; We numerically demonstrate a new fiber laser architecture supporting spectral compression of negatively chirped pulses in passive normally dispersive fiber. Such a process is beneficial for improving the energy efficiency of the cavity as it prevents narrow spectral filtering from being highly dissipative. The proposed laser design provides an elegant way of generating transform-limited picosecond pulses.
Optical Cavity-Less 40-GHz Picosecond Pulse Generator in the Visible Wavelength Range
2019
International audience; High-repetition-rate optical frequency-comb sources emitting picosecond pulses play important roles in variousscientific researches and industrial applications. Such ultrafast pulse sources are mostly generated in opticalcavities or microresonators. By means of the wavelength-conversion techniques, it is possible to transfer thecavity-based near-IR robust and compact sources to the mid-IR or to the visible wavelength regions [1-2], forwhich there is an increasing demand, for biophotonics and other applications. Here we demonstrate the generationof high-repetition-rate picosecond pulses in the visible wavelength range by using a fully optical cavity-lessconfiguration.…
Integrated low drive voltage electro-optic Bragg modulator using a, periodically poled lithium niobate
2017
Periodically poled lithium niobate (PPLN) is currently used for frequency conversions using quasi-phase-matching, thanks to its high nonlinear coefficients and mature poling process. PPLN can also be attractive for electro-optic (EO) applications. Several studies have been conducted on PPLN-based EO deflectors, and recent realizations have lower the required applied voltage under hundred volts [1]. Indeed, for practical EO applications drive voltages as low as 5 V are usually required. For this purpose, we use a recent technique to realize high-quality isolated crystalline film out of LN [2] to implement an EO Bragg deflector with a drive voltage below 10 V. In this work we present an effic…
Bistable Device based on the Kerr Effect in a Microfiber Resonator
2007
We propose a bistable device based on the Kerr effect in a microfiber resonator. Our simulations show that low switching powers (in the order of a few tens of mW) are expected with tellurite microfibers.
Spatio-Temporal Beam Mapping for Studying Nonlinear Dynamics in Graded Index Multimode Fiber
2020
We experimentally demonstrate high-resolution mapping of the spatio-temporal dynamics of the beam cleaning process in graded index multimode fibers. This high-resolution characterization reveals the time-dependent nature of the beam self-cleaning process.
Kerr Beam Self-Cleaning in Multimode Fibers
2018
We overview recent experimental results of beam self-cleaning observed in various types of multimode fibers. We analyze the output spatial beam shapes and their connection with the refractive index profile of the fibers.
Single photon MIR upconversion detector at room temperature with a PPLN ridge waveguide
2019
International audience; In this paper we describe an upconversion detector in the mid infrared (around 3.5 μm). We take advantage of the PPLN ridge waveguide technology to achieve single photon detection at room temperature on a single spatial mode. With a pump power of 192 mW we obtain a detection efficiency of 0.4% for 22k dark count per second, which corresponds to a noise equivalent power of 3.0 fW · Hz−1/2 and an internal conversion efficiency of 85 %/W of pump.
Low drive voltage electro-optic Bragg deflector using a periodically poled lithium niobate planar waveguide
2016
International audience; An electro-optic Bragg light deflector is demonstrated in a thinned, periodically poled lithium niobate planar waveguide confined between two silica layers on a silicon substrate. More than 97% of diffraction efficiency is obtained with an operating wavelength of 633 nm for the two orthogonal light polarizations with a drive voltage of about 5 V. The temporal electric drift and the response time of the component are also studied.