We report active Q-switching of an all-fiber laser using a Bragg grating based acousto-optic modulator.Q-switching is performed by modulating fiber with extensional acoustic wave.The wave modulates periodically the effective index profile FBG and changes its reflection features.This allows controlling Q-factor cavity.Using 1 m 300 ppm erbium-doped maximum pump power 180 mW, Q-switch pulses 10 W peak 82 ns wide were generated.The pulse repetition rate can be continuously varied from few Hz up...

Q-switching of fiber lasers using bulk elements has important drawbacks as reduced mechanical stability and high insertion losses. The development efficient all-fiber modulation techniques is the key to obtain robust, compact Q-switched lasers. Certainly, Bragg gratings (FBG) been crucial make progress on FBGs permit a simple way assemble laser cavities can be written in active itself. Q-factor this type determined by reflectivity losses fiber. Here, we focus use magnetostrictive materials...

The elasto-optic effect in optical fibers under axial strain can be characterized by means of the whispering gallery mode (WGM) resonances fiber itself. This technique enables a direct measurement anisotropy, determination individual Pockels' coefficients, and study wavelength dependence. method is based on rigorous theoretical WGM cylindrical microresonators. shift as function was measured for TE TM modes, showing strong modal anisotropy. In particular, rate modes 1.84 times one modes. From...

We present an all-optical novel configuration for implementing multitap transversal filters by use of a broadband source sliced fiber Bragg grating arrays generated propagating acoustic wave along strong uniform grating. The tunability and reconfigurability the microwave filter are demonstrated.

In this letter, we present the fabrication of a microstructured fiber with high birefringence suitable for nonlinear applications. The has been fabricated adapting stack and draw method fibers. is achieved inducing ellipticity to air-hole array by controlling lateral tension between preform jacketing tube. Values group index higher than 7/spl times/10/sup -3/ are demonstrated.

Active mode locking of an erbium-doped all-fiber laser with a Bragg-grating-based acousto-optic modulator is demonstrated. The fiber Bragg grating was acoustically modulated by standing longitudinal elastic wave, which periodically modulates the sidebands at twice acoustic frequency. has Fabry-Perot configuration in cavity loss modulation achieved tuning output to one induced sidebands. Optical pulses 9 MHz repetition rate, 120 mW peak power, and 780 ps temporal width were obtained. results...

U-shaped tight curvatures in optical fibers lead to resonant couplings between the fundamental and higher order modes that are sensible different parameters, such as strain or temperature, for example. The response of sensor consists on shift wavelength coupling. In case singlemode fibers, coupling involves a so-called "cladding mode" and, due its evanescent field, curved region will be changes external medium, well. this paper, we present fabrication characterization robust, easy-to-make,...

We report a novel dynamic fiber-optic add-drop multiplexer that combines the properties of Bragg gratings and acousto-optic effect in optical fibers. It is noninterferometric, nonfrequency shifting device allows adding/dropping certain channel when it required. The prototype presented here exhibits time response /spl sim/95μs.

We report a wavelength-switchable fiber ring laser that includes Bragg grating-based acoustooptic superlattice modulator. Wavelength switching of the emission is achieved by controlling peak reflectivity different reflection bands appear on both sides wavelength when longitudinal acoustic wave propagates along grating.

This letter presents a single mode, actively Q-switched distributed feedback fiber laser. Acoustic pulses are launched into an erbium-doped Bragg grating, resulting in the introduction of traveling defect. Thus, transmission peak appears reflection band while pulse travels along grating. effect allows laser to operate regime, providing optical which repetition rate was continuously tuned up 10kHz. Pulses 168mW power and 73ns temporal width were obtained at low rate.

Nanometric narrowband long period gratings (LPGs) are investigated for the implementation of improved fiber optic biosensors. The reduction more than one order magnitude in linewidth LPG with respect to standard at 1500 nm leads improvement resolution sensor. By selecting proper fabrication parameters (high numerical aperture, relatively high mode, and large length), LPGs a 3-dB bandwidth 1.5 were fabricated. sensitivity as refractometer was calculated experimentally characterized detail. In...

An acoustically Q-switched distributed feedback fiber laser with enhanced performance is presented. It based on an FBG written in erbium doped fiber, which a dynamic defect introduced by means of short acoustic pulse. The the depends reflectivity grating. In this work, we present two different lasers realized active gratings reflectivities. Both are characterized at pump powers and repetition rates. shown that weaker grating was significantly improved respect to stronger terms peak power,...

The polarization-dependent guiding properties of a hexagonal-lattice photonic crystal fiber with solid-core surrounded by four large air holes are investigated. appearance polarization dependent cutoff frequency, together several parameters as the birefringence, modal effective area, group velocity dispersion and loss analyzed. A collection fibers different structural were fabricated characterized. An anti-guide structure from at least 450 nm to 1750 nm, polarizing 16 dB/m 1550 an endlessly...

Abstract We report on the experimental and theoretical analysis of parametrical optomechanical oscillations in hollow spherical phoxonic whispering gallery mode resonators due to radiation pressure. The optically excited acoustic eigenmodes cavity oscillate regeneratively leading parametric oscillation instabilities.

The nanostructuration of biolayers has become a paradigm for exploiting nanoscopic light-matter phenomena biosensing, among other biomedical purposes. In this work, we present photopatterning method to create periodic structures biomacromolecules based on local and mild denaturation protein mediated by UV-laser irradiation. These nanostructures are constituted modulation the activity, so they free topographic compositional changes along pattern. Herein, introduce approach, explore patterning...

This Letter reports on the fabrication of long period fiber gratings having subnanometric bandwidths in 1500 nm spectral region. Large have been photo inscribed a high NA fiber; grating pitch and order HE cladding mode are optimized to produce with large number periods prevent coupling TE, TM, or EH modes. Resonances FWHM 0.83 0.68 achieved for 15 20 cm long, respectively; free range between transmission notches is 125 nm. The polarization effects sensitivity temperature strain variations...

Abstract Opto‐mechanical interactions in different photonic platforms as optical fibers and microresonators are raising great attention, new exciting achievements have been reported the last few years. Transverse acoustic mode resonances (TAMRs) –which can be excited optically via electrostriction generate forward Brillouin scattering (FBS)– being promoted physical mechanism for fiber‐sensing concepts. Here, study reports a novel approach to detect characterize opto‐excited TAMRs of an fiber...

Experimental results are presented for the dependence of dispersion and birefringence a highly birefringent photonic crystal fibre with temperature. It is shown that, unlike conventional optical fibres, where temperature induces stress regions between different materials present in their structure, fibres exhibit no these properties owing to single material nature structures.

A linearly polarized all-fiber erbium laser is presented in this work. The polarization selective element consists on a piece of single-mode, polarizing microstructured fiber, which placed within the cavity. fiber shows regular lattice air-holes, four holes next to core were enlarged. This dependent loss 16 dB/m around 1550 nm. cavity presents different losses for each and, as consequence, highly emission obtained. ratio emitted power was excess 20 dB.