Enhancement of stimulated Brillouin scattering of higher-order acoustic modes in single-mode optical fiber

This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=ol-30-20-2685. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Solving the elastic wave equation exactly for a GeO2-doped silica fiber with a steplike distribution of the longitudinal and shear velocities and density, we have obtained the dispersion, attenuation, and fields of the leaky acoustic modes supported by the fiber. We have developed a model for stimulated Brillouin scattering of these modes in a pump-probe configuration and provided their Brillouin gains and frequencies for an extended range of core sizes and GeO2 doping. Parameter ranges close to cutoff of the acoustic modes and pump depletion enhance the ratio of higher-order peaks to the main peak in the Brillouin spectrum and are suitable for simultaneous strain-temperature sensing.Shahraam Afshar V., V. P. Kalosha, Xiaoyi Bao, Liang Che

Design considerations for large-aperture single-mode oxide-confined vertical-cavity surface-emitting lasers

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 101, 071117 (2012) and may be found at https://doi.org/10.1063/1.4746422.The output modal content of the oxide-confined vertical-cavity surface-emitting lasers (VCSELs) crucially depends upon the thickness of the low-index oxide aperture, its position with respect to the standing waves of the transverse-longitudinal modes and the separation from the cavity. Three-dimensional cold-cavity optical modes of typical AlGaAs/GaAs VCSELs at 850 nm were simulated to study these dependencies quantitatively taking into account the field diffraction and the material dispersion. Modification of one or two periods of the distributed Bragg reflector by positioning the thin oxidized aperture layers in the mode nodes allows single-mode regime to extend to the aperture diameters as large as 10 μm.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

High brightness photonic band crystal semiconductor lasers in the passive mode locking regime

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 105, 161101 (2014) and may be found at https://doi.org/10.1063/1.4899129.High brightness photonic band crystal lasers in the passive mode locking regime are presented. Optical pulses with peak power of 3 W and peak brightness of about 180 MW cm−2 sr−1 are obtained on a 5 GHz device exhibiting 15 ps pulses and a very low beam divergence in both the vertical and horizontal directions.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

1.9 W continuous-wave single transverse mode emission from 1060 nm edge-emitting lasers with vertically extended lasing area

This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared in Appl. Phys. Lett. 105, 151105 (2014) and may be found at https://doi.org/10.1063/1.4898010.High-brightness edge-emitting semiconductor lasers having a vertically extended waveguide structure emitting in the 1060 nm range are investigated. Ridge waveguide (RW) lasers with 9 μm stripe width and 2.64 mm cavity length yield highest to date single transverse mode output power for RW lasers in the 1060 nm range. The lasers provide 1.9 W single transverse mode optical power under continuous-wave (cw) operation with narrow beam divergences of 9° in lateral and 14° (full width at half maximum) in vertical direction. The beam quality factor M2 is less than 1.9 up to 1.9 W optical power. A maximum brightness of 72 MWcm−2sr−1 is obtained. 100 μm wide and 3 mm long unpassivated broad area lasers provide more than 9 W optical power in cw operation.DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelement

INFLUENCE OF SILVER SURFACE STRUCTURE ON LUMINESCENCE CHARACTERISTICS OF EUROPIUM DOPED POLYMER FILMS

The luminesceuce characteristics of Eu 3+ ions in Eu(ΝO 3 ) 3 . 6Η2O salt contained in polymer films coating the silver metallic surfaces were studied. The surfaces were specially prepared to consist of silver tip arrays with the height of tips in micron and surface density in 10 -8 cm -2 ranges. The eval-. uation of enhancement per one europium ion gave a value 3.5 x 10 2 for one polymer layer coating of tip array silver surface in comparison with the case of glass substrate coating

Self-mode-locking of cw solid-state lasers with a nonlinear antiresonance ring Self-mode-locking of cw solid-state lasers with a nonlinear antiresonance ring

Abstract. An analysis is made of self-mode-locking of cw solid-state lasers performed by a modulator based on an antiresonance ring containing a bulk element with self-phase -modulation. Such a modulation is capable of effectively discriminating fluctuations of radiation and has a high initial transmission. The characteristics of a self-consistent ultrashort pulse, obtained from an approximate analytic solution of the problem of cw lasing, are investigated as a function of the modulator parameters. The parameters of a system for which an analytic solution matches the regions of effective self-mode-locking are found by numerical modelling of formation of stable ultrashort pulse trains from the noise radiation in an active medium subjected to continuous pumping

SELF-MODELOCKING OF CW SOLID-STATE LASERS BY NONLINEAR KERR POLARIZATION MODULATOR Downloaded From: http://spiedigitallibrary.org/ on 04/12/2013 Terms of Use: http://spiedl.org/terms

ABSTRACT Numerical simulation of seif-modelocking of cw solid-state lasers with Kerr polarization modulator is developed. The limited ranges of laser and modulator parameters within which the laser generates stable train of ultra-short pulses are given. Recently a new attractive modelocking technique has been demonstrated for cw Ti:sapphire laser generated 2OO fs pulses"2. It utilized fast optical Kerr effect consisting in self-precession of field vibration effipse proportional to intensity. The modulators based on this effect were proposed in Ref. Numerical model includes the investigation of temporal shaping of generation field V(t) by multiple transits through gain media, spectral filter of Fabri-Perot type and Kerr polarization modulator. In the rate-equation approximation for cw pumping of four-level active media like Ti:sapphire the gainA is given by the equation'3 dA / dt = U4 (Am A)I C32 AIVI2 A/Ta, where C14 and a32 are the absorber and emission cross sections of laser medium, Am 5 the maximum gain for full population inversion, I is the pump intensity, Ta 5 the gain relaxation time, t is local time in temporal window equal to cavity period Tcav. The generation field is amplified by factor g = exp(A -F), where r s the linear cavity losses. The algorithm of spectral filter action was chosen to be the same as in Ref. 14-15. Fabry-Perot etalon as a spectral filter is characterized by transit time equal to the mesh time spacing At and by characteristic memory time t1 defined by reflectivity of etalon surfaces. Assuming the linear polarization of laser field, the simplest design for Kerr polarization modulator is to be as follows: quarter-wave birefrigent plate creating the effiptical polarization, Kerr medium sample changing the angle of inclination of vibrational effipse and analyzer. Let a be the angle between the polarization of input field and A /4-plate main axis. Then the analysis3 gives the angle of self-precession of effipse major axis =p Ivl2sin2

Using Nonuniform Fiber to Generate Slow Light via SBS

The data pulse delay based on slow light induced by stimulated Brillouin scattering (SBS) in a nonuniform dispersion decreasing fiber (DDF) is demonstrated experimentally, and the distortions of data pulses at different beat frequencies are studied. We found that a delay exceeding a pulse width can be achieved at particular beat frequency, and the DDF has larger delay versus gain slope coefficient with much better output pulse quality than single-mode fiber

Research Letter Using Nonuniform Fiber to Generate Slow Light via SBS

The data pulse delay based on slow light induced by stimulated Brillouin scattering (SBS) in a nonuniform dispersion decreasing fiber (DDF) is demonstrated experimentally, and the distortions of data pulses at different beat frequencies are studied. We found that a delay exceeding a pulse width can be achieved at particular beat frequency, and the DDF has larger delay versus gain slope coefficient with much better output pulse quality than single-mode fiber