Search results for "PHOSFOS"
showing 10 items of 51 documents
Nonlinear effects above 2 µm in chalcogenide suspended core microstructured optical fibers: Modeling and experiments
2011
We present our latest results on the linear and nonlinear modeling, and on the fabrication of chalcogenide suspended core microstructured optical fibers for mid-infrared generation. We focus on an AsSe glass composition. We have used a thulium-doped fiber laser to pump our fibers around 2 µm. In order to enhance further the nonlinearities and to manage the chromatic dispersion for supercontinuum application, we have tapered some of our microstructured optical fibers.
Actively Q-switched all-fiber lasers
2007
Q-switching of fiber lasers using bulk elements has important drawbacks as reduced mechanical stability and high insertion losses. The development of efficient all-fiber modulation techniques is the key to obtain robust, compact and efficient Q-switched all-fiber lasers. Certainly, the development of fiber Bragg gratings (FBG) has been crucial to make progress on fiber lasers. FBGs permit a simple way to assemble all-fiber laser cavities and can be written in the active fiber itself. The Q-factor of this type of cavities is determined by the reflectivity of the FBGs and the losses of the fiber. Here, we focus on the use of magnetostrictive materials and the acousto-optic interaction to deve…
Radiation Vulnerability of Fiber Bragg Gratings in Harsh Environments
2015
International audience; The difficulties encountered in the implementation of a temperature or strain sensor based on fiber Bragg grating (FBG) in a harsh radiative environment are introduced. We present the choices made to select both a radiation-resistant fiber in terms of transmission and also the grating inscription conditions necessary to write radiation tolerant FBGs in such fibers with a femtosecond laser. The radiation response of these gratings was also studied under radiation at dose up to 1 MGy. The comparison between Ge-free and Ge-doped fibers was highlighted.
Asymmetrically Apodized Fiber Bragg Gratings for Applications in Dispersion-Less Fabry-Pérot Fiber Cavities
2010
Abstract This article presents a theoretical study of the dispersion properties of the asymmetrically apodized fiber Bragg gratings. It is shown that the dispersive behavior of these gratings may be changed from normal to anomalous, depending on the apodization function and the grating strength. The asymmetrical Bessel functions were chosen in order to demonstrate these properties of the gratings. The application of this effect in a dispersion-less Fabry-Perot fiber cavity formed by two asymmetrically apodized fiber Bragg gratings is discussed.
Dynamic Bragg gratings induced in erbium-doped fiber at phase-Modulated beams' coupling
2005
We present the results of an experimental study of dynamic amplitude and phase Bragg gratings induced in a heavy-doped erbium fiber at the wavelengths 1532 and 1538 nm under the 980-nm pumping. The technique of two phase-modulated beams' coupling was applied for an experimental measurement of the changes in refractive index and gain accompanying the gratings' formation in the fiber, and an analysis based on the Kramers-Kronig Relations for the fiber absorption/gain spectra and two-pass amplifying was performed for modeling these changes.
Linearly polarized all-fiber laser using a short section of highly polarizing microstructured fiber
2007
A linearly polarized all-fiber erbium laser is presented in this work. The polarization selective element consists on a piece of a single-mode, polarizing microstructured fiber, which is placed within the laser cavity. The microstructured fiber shows a regular lattice of air-holes, in which four holes next to the core were enlarged. This fiber shows a polarization dependent loss of 16 dB/m around 1550 nm. The laser cavity presents different losses for each polarization and, as a consequence, a highly polarized emission is obtained. The polarization ratio of the emitted power was in excess of 20 dB.
Tunable dispersion device based on a tapered fiber Bragg grating and nonuniform magnetic fields
2003
We present a new variable dispersion device based on tuning the chirp of a tapered fiber Bragg grating by means of a magnetic transducer. By using a nonuniform magnetic field, we demonstrate a 188-472-ps/nm dispersion tuning range, suitable for tunable radio-frequency filters and dispersion compensation, among others.
Electrically tunable photonic true-time-delay line
2010
We present a new application of the acousto-optic superlattice modulation of a fiber Bragg grating based on the dynamic phase and group delay properties of this fiber-optic component. We demonstrate a tunable photonic true-time-delay line based on the group delay change of the light reflected from the grating sidebands. The delay is electrically tuned by adjusting the voltage applied to a piezoelectric transducer that generates the acoustic wave propagating along the grating. In our experiments, a true-time delay of 400 ps is continuously adjusted (300 ps within the 3 dB amplitude range of the first sideband), using a 12 cm long uniform grating.
Chromatic Dispersion Control in Mode-Locked Yb-Doped Fiber Lasers Based on a Microstructured Optical Fiber
2013
We present an experimental study on the use of solid core microstructured optical fibers (MOF) for managing the chromatic dispersion in an Yb-doped fiber laser passively mode-locked by a saturable absorber. The performance of the laser, in terms of pulse width and repetition rate, was investigated as a function of the net cavity dispersion.
Fast response vibration sensor based on Bragg gratings written in tapered core fibres
2007
Bragg gratings written in tapered core fibres permit a direct measure of mechanical vibrations with a time response better than 10 µs. The intrinsic properties of the sensors lead to a simple interrogation technique and wavelength multiplexing capacity. The sensor system is operated at 800 nm and is compact and low-cost.