Search results for " photonic"
showing 10 items of 720 documents
Pulsed X‐Ray Radiation Responses of Solarization‐Resistant Optical Fibers
2018
International audience; The transient radiation‐induced attenuation (RIA) of two different versions of pure‐silica‐core (PSC) multimode optical fibers (so‐called “solarization‐resistant” fibers) exposed to nanosecond 1 MeV X‐ray pulses are investigated. On‐line RIA spectra measurements at both room temperature (RT) and liquid nitrogen temperatures (LNT) in the range 1–3.5 eV are performed. Following the RIA kinetics, the properties of the metastable defects that are bleached just after the pulse are discussed. The spectral decomposition of the RIA is performed using known Gaussian bands associated to point defects absorbing in this spectral range. For both fiber types, the generation and th…
Performance Analysis of a Prototype High‐Concentration Photovoltaic System Coupled to Silica Optical Fibers
2021
High-concentration photovoltaic (HCPV) systems are one of the most promising technologies for the generation of renewable energy with high-conversion efficiency. Their development is still at an early stage, but the possibility of integrating high-concentration systems into buildings offers new opportunities to achieve the net-zero-energy building goal. Herein, the optical and energetic performance of a hybrid daylighting−HCPV prototype based on pure- or doped-silica optical fibers (OFs) to guide 2000× concentrated sunlight inside the buildings is evaluated. There, the light can either be used to illuminate interior spaces or projected on solar cells to generate electricity. The system equi…
Effect of wavelength dependence of nonlinearity, gain, and dispersion in photonic crystal fiber amplifiers
2005
Photonic crystal fibers are used in fiber amplifiers and lasers because of the flexibility in the design of mode area and dispersion. However, these quantities depend strongly on the wavelength. The wavelength dependence of gain, nonlinearity and dispersion are investigated here by including the wavelength dependence explicitly in the nonlinear Schr\"odinger equation for photonic crystal fibers with varying periods and hole sizes. The effect of the wavelength dependence of each parameter is studied separately as well as combined. The wavelength dependence of the parameters is shown to create asymmetry to the spectrum and chirp, but to have a moderating effect on pulse broadening. The effect…
Demonstration of Stimulated-Raman-scattering suppression in optical fibers in a multifrequency pumping configuration
1999
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…
Coating impact and radiation effects on optical frequency domain Reflectometry fiber-based temperature sensors
2015
International audience; Temperature response of radiation-tolerant OFDR-based sensors is here investigated, with particular attention on the impact of coating on OFS. By performing consecutive thermal treatments we developed a controlled system to evaluate the performances of our distributed temperature sensor and to estimate the radiation impact. We show an important evolution of the temperature coefficient measurements with thermal treatments for non-irradiated fiber and that the amplitude of this change decreases increasing radiation dose. As final results, we demonstrate that sensor performances are improved if we performed a pre-thermal treatment on the fiber-based system permitting to…
Cascadability and reshaping properties of a saturable absorber inserted inside a RZ transmission line for future 160-Gbit/s all-optical 2R-regenerato…
2007
International audience; In this prospective work, we analyze the behavior of a quantum-well microcavity saturable absorber component cascaded into a 100-km SMF RZ transmission line in order to annihilate the ghost-pulse phenomenon in the following simplified “...010101...” 160-Gbit/s 2-bit pattern at 1555 nm. Recirculating-loop experiments show a maximal ghost-pulse extinction up to 11.6 dB as well as an intensity extinction ratio enhancement higher than 6 dB over at least 800 km of propagation.
Q switching and mode locking pulse generation from an all-fiber ring laser by intermodal acousto-optic bandpass modulation
2018
Q-switched and mode-locked (QML) pulse generation from an all-fiber ring laser based on intermodal acousto-optic bandpass modulation is reported. The modulator relies on full-acousto-optic mode re-coupling cycle induced by a standing flexural acoustic wave, with a transmission response that is controlled by amplitude modulation of the acoustic wave signal. The Q factor of the cavity is controlled by a rectangular pulse wave with variable frequency and duty cycle, whereas mode locking is achieved by amplitude modulation derived from a standing flexural acoustic wave. The best QML pulses were obtained at 0.5 kHz repetition rate, with a pump power of 549.2 mW, at the optical wavelength of 1568…
Silicon-microring into a fiber laser cavity for high-repetition-rate pulse train generation
2017
International audience; In 1997, Yoshida et al. inserted a Fabry-Perot filter in a modulation instability fiber laser cavity [1], the free spectral range (FSR) of the Fabry-Perot fixed the RF to 115 GHz; however the pulsed laser was poorly stable. Since then, lasers of increasing performance have been demonstrated using variants of this method. In 2012, Peccianti et al., demonstrated the first fiber laser harmonically mode-locked by integrated high-finesse microresonator [2]. The doped silica, on-chip microresonator provided both high spectral selectivity and nonlinearity, thus promoting the dynamics pulsed at 200 GHz. By using a silicon microring resonator (SMRR), this approach lead to the…
Measurement of Pockels’ coefficients and demonstration of the anisotropy of the elasto-optic effect in optical fibers under axial strain
2016
The elasto-optic effect in optical fibers under axial strain can be characterized by means of the whispering gallery mode (WGM) resonances of the fiber itself. This technique enables a direct measurement of the anisotropy, the determination of the individual Pockels' coefficients, and the study of the wavelength dependence. The method is based on a rigorous theoretical study of WGM resonances in cylindrical microresonators. The shift of the WGM resonances as a function of strain was measured for the TE and TM modes, showing a strong modal anisotropy. In particular, the shift rate for TE modes was 1.84 times the one for TM modes. From these measurements, experimental values for the Pockels' …
Stable Optically Generated RF Signals from a Fibre Mode-Locked Laser
2010
Phase stability of RF signals obtained by two-mode filtering of a fibre mode-locked laser is analyzed. Time jitter is shown to be constant with selected mode spacing, confirming the scheme capability for generating stable RF signals up to extremely-high frequency.