Search results for " optical fiber"
showing 10 items of 327 documents
Tunable all-optical negative multitap microwave filters based on uniform fiber Bragg gratings.
2003
We present a novel and simple technique for obtaining transversal filters with negative coefficients by using uniform fiber Bragg gratings. We demonstrate a wide tuning range, good performance, low cost, and easy implementation of multitap filters in an all-optical passive configuration in which negative taps are obtained by use of the transmission of a broadband source through uniform Bragg gratings.
Fiber laser switched by a long period grating interferometer as an intra-cavity loss modulator
2010
Abstract In this paper we present an actively switched fiber laser with an all-fiber long-period grating-based interferometer used as an intra-cavity loss modulator. The modulator consists of two equal long-period gratings written sequentially in the same piece of a double-clad optical fiber. One of the gratings is fixed onto a piezoceramic cylinder producing fast modulation of the interferometer transmission spectrum. The laser demonstrates a stable regime of pulsed emission at repetition rates in the range of tens of kHz.
Q-switching of an all-fiber laser by acousto-optic modulation of a fiber Bragg grating.
2009
We report active Q-switching of an all-fiber laser using a Bragg grating based acousto-optic modulator. Q-switching is performed by modulating a fiber Bragg grating with an extensional acoustic wave. The acoustic wave modulates periodically the effective index profile of the FBG and changes its reflection features. This allows controlling the Q-factor of the cavity. Using 1 m of 300 ppm erbium-doped fiber and a maximum pump power of 180 mW, Q-switch pulses of 10 W of peak power and 82 ns wide were generated. The pulse repetition rate of the laser can be continuously varied from few Hz up to 62.5 kHz.
Manufacturing of All-Fiber Q-Switch lasers for supercontinuum generation
2016
This work exposes the fabrication process of an All-Fiber Q-Switch laser and its use as a pump source for the generation of supercontinuum (SCG) with tapered microstructured fiber devices (tapers).
Tunable Dispersion Compensator Based on a Fiber Bragg Grating Written in a Tapered Fiber
2004
We report a novel dispersion tunable device for first-order dispersion compensation. It is based on a fiber Bragg grating written in a tapered fiber with a specific profile. The taper profile allows tuning the dispersion of the grating by stretching the fiber while the linearity of the group delay is preserved. A device with 0.8 nm of useful bandwidth and dispersion value tunable over more than 400 ps/nm is reported.
Radiation hardening of FBG in harsh environments
2014
International audience; The difficulties encountered in the implementation of a temperature or strain sensor based on Fiber Bragg Grating 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 femto-second laser. The response of different classes of gratings was also studied under radiation at high doses (>1MGy). The comparison between F- and Ge-doped fibers was highlighted.
Ultra-flat SPM-broadened spectra in a highly nonlinear fiber using a fiber Bragg grating based parabolic pulse shaper
2006
We demonstrate the generation of ultra-flat broadened spectra by seeding a nonlinear fiber with parabolic pulses shaped using a fiber grating. Applications in pulse compression and spectral slicing are shown.
Measurement of temperature profile induced by the optical signal in fiber Bragg gratings using whispering-gallery modes.
2014
The temperature sensitivity of whispering-gallery mode resonances of an optical fiber is exploited to measure thermal effects induced by an optical signal of moderate power along a fiber Bragg gating (FBG). The UV inscription technique used for the fabrication of FBG introduces a permanent change in the absorption coefficient of the fiber; thus, thermal effects are expected. The resonance wavelength shift of whispering-gallery modes provides information about the temperature change in the fiber, point to point. We present the experimental characterization of the thermal effects in FBG as a function of the wavelength and the power of the launched optical signal through the grating.
Fiber laser with cladding-mode feedback based on intracavity long period grating
2011
Cladding modes in fiber laser technology have considerable interest for dispersion compensation [1] and power scaling [2, 3]. A fiber laser with core-cladding conversion was made in convectional Erbium doped fiber by a combination of Bragg and external cavity mirrors and blocking the fundamental mode with a damaged core fiber [2]. Furthermore, the insertion of two long period gratings (LPG) in a fiber Bragg gratings (FBG) Fabry-Perot cavity has been proposed as a potential high-order-mode fiber laser [3]; however, no experimental demonstration has been reported yet because there are no ring-doped fibers available in the market. In this work, we present the first demonstration of an all-fibe…
Determination of the position of defects generated within a chirped fiber Bragg grating by analyzing its reflection spectrum and group delay
2016
We determinate the position of defects generated within a chirped fiber Bragg grating by analyzing its reflection spectrum and group delay. Simulations were performed by using the T-matrix method for different defect locations.