Query: stabilization of broad area semiconductor lasers

Candidate papers:

abstract: Broad Area Semiconductor edge emitting lasers typically display self focusing nonlinearity due to the refractive index dependence on the population inversion. It induces the homogeneous solution instability, multi transverse mode operation and filamentation. This behavior strongly deteriorates the beam quality and drastically reduces their applicability. We suppress this instability for semiconductors with small enough linewidth enhancement factors, aH, by the introduction of a single spatial modulation in the transverse and longitudinal directions. For large aH values, optimized multi frequency spatial modulations are needed. The proposed scheme becomes especially interesting for high nonlinearities that correspond to the normal laser operation.
author_names: Subindu Kumar

Waqas W Ahmed

Ramon Herrero

Muriel Botey

Kestutis Staliunas
title: Stabilization of broad area semiconductor lasers
venue: OPTO
year: 2017

abstract: We show that the emission of broad area semiconductor amplifiers and lasers can be efficiently stabilized by introducing two dimensional periodic modulations simultaneously on both the refractive index and the pump (gain loss) profiles in the transverse and longitudinal directions. The interplay between such index and gain loss modulations efficiently suppresses the pattern forming instabilities, leading to highly stable and bright narrow output beams from such sources. We also determine the stabilization performance of the device as a function of the pump current and linewidth enhancement factor.
author_names: Waqas W Ahmed

Shubham Kumar

J Medina

Muriel Botey

Ramon Herrero

Kestutis Staliunas
title: Stabilization of broad area semiconductor laser sources by simultaneous index and pump modulations.
venue: Optics letters
year: 2018

abstract: Broad Area Semiconductor Amplifiers and Lasers display instability of the homogeneous state typically related with self focusing nonlinearities, inducing multi transverse mode operation and filamentation that deteriorates the beam quality. We show that the emission of these amplifiers and lasers can be efficiently stabilized by introducing simultaneous modulations of pump and refractive index in transverse and longitudinal directions. The pattern forming instabilities are efficiently suppressed even for the case of large linewidth enhancement factors by the intertwinement between both inphase modulations leading to stable beams.
author_names: Waqas W Ahmed

Shubham Kumar

J Medina

Muriel Botey

Ramon Herrero

Kestutis Staliunas
title: Stabilization of Broad Area Semiconductor Amplifiers and Lasers by Double Modulation of Pump and Refractive Index
venue: 2018 20th International Conference on Transparent Optical Networks (ICTON)
year: 2018

abstract: A new fully integrated wavelength stabilization scheme based on grating coupled surface emitting lasers is explored. This wavelength stabilization scheme relies on two gratings. The first grating is fabricated on the p side of the semiconductor laser in close proximity to the laser waveguide such that it couples light out of the guided mode of the waveguide into a propagating mode in the substrate; this grating is known as the grating coupler. The second grating is fabricated on the n side of the substrate such that for the stabilization wavelength, this second grating operates in the Littrow condition and is known as the feedback grating. Furthermore with the proper design of the two gratings, the feedback grating will operate under total internal reflection conditions allowing a near unity retro reflection of the light of the stabilization wavelength. The grating coupler and feedback grating together comprise a dual grating reflector (DGR) The DGR wavelength stabilization scheme is investigated both theoretically by means of numerical modeling and experimentally by integration of a DGR as a wavelength selective reflector into a single quantum well semiconductor laser with a gain peak centered at 975nm. Numerical modeling predicts a peak reflection of approximately 70% including losses and a spectral width of 0.3nm. The integration of a DGR into a semiconductor laser proved both the efficacy of the scheme and also allowed us to experimentally determine the effective reflectivity to be on the order of 62% the spectral width of light output from these devices is typically on the order of 0.2nm. Furthermore, these devices had light current characteristic slopes greater than 0.84W/A operating under continuous wave conditions. The DGR was then modified to provide a reflection with two spectral peaks. A semiconductor device incorporating this dual wavelength
author_names: Jason K O'Daniel
title: Integrated Wavelength Stabilization Of Broad Area Semiconductor Lasers Using A Dual Grating Reflector
year: 2006

abstract: We propose the stabilization of the output beam of Broad Area Semiconductor (BAS) amplifiers through the introduction of a spatially periodic modulated potential. We show that a periodic modulation of the pump profile in transverse and longitudinal directions, under certain 'resonance' condition, can solve two serious problems of BAS amplifiers (and possibly lasers) which are (i) the lack of an intrinsic spatial mode selection mechanism in linear amplification regimes and (ii) the modulation instability (also called Bespalov Talanov instability) in nonlinear regimes. The elimination of these two drawbacks can significantly improve the spatial quality of the emitted beam in BAS amplifiers.
author_names: S Kumar

Waqas W Ahmed

Ramon Herrero

Muriel Botey

Mindaugas Radziunas

Kestutis Staliunas
title: Stabilization of Broad Area Semiconductor Amplifiers by Spatially Modulated Potentials
year: 2016

abstract: AbstractA 2 1 dimensional PDE traveling wave model describing spatial lateral dynamics of edge emitting broad area semiconductor devices is considered. A numerical scheme based on a split step Fourier method is presented. The domain decomposition method is used to parallelize the sequential algorithm. The parallel algorithm is implemented by using Message Passing Interface system, results of computational experiments are presented and the scalability of the algorithm is analyzed. Simulations of the model equations are used for optimizing of existing devices with respect to the emitted beam quality, as well as for creating and testing of novel device design concepts.
author_names: Mindaugas Radziunas

Raimondas Ciegis
title: Effective Numerical Algorithm for Simulations of Beam Stabilization in Broad Area Semiconductor Lasers and Amplifiers
year: 2014

abstract: The simulation of spectral stabilization of broad area edge emitting semiconductor diode lasers is presented in this paper. In the reported model light temperature and charge carrier distributions are solved iteratively in frequency domain for transverse slices along the semiconductor heterostructure using wide angle finite difference beam propagation. Depending on the operating current the laser characteristics are evaluated numerically, including near and far field patterns of the astigmatic laser beam, optical output power and the emission spectra, with central wavelength and spectral width. The focus of the model lies on the prediction of influences on the spectrum and power characteristics by frequency selective feedback from external optical resonators. Results for the free running and the spectrally stabilized diode are presented.
author_names: Carlo Holly

Stefan Hengesbach

Martin Traub

Dieter Hoffmann
title: Simulation of spectral stabilization of high power broad area edge emitting semiconductor lasers.
venue: Optics express
year: 2013

abstract: Four different external resonator concepts including VBGs for spectral stabilization of HPDLs are modelled and numerically evaluated to be compared to each other with respect to stabilization efficiency and sensitivity to the "smile error" The coupled resonators including the external system and the diode laser are solved with a Fox Li approach. The paper gives a brief summary about the applied simulation model and proceeds with the results for the different feedback concepts. The effective reflectivity, losses in the optical system, losses due to the back coupling into the waveguide and the averaged optical confinement factor are calculated.
author_names: Carlo Holly

Stefan Hengesbach

Martin Traub

Dieter Hoffmann
title: Numerical analysis of external feedback concepts for spectral stabilization of high power broad area semiconductor lasers
venue: Photonics West Lasers and Applications in Science and Engineering
year: 2014

abstract: The lateral modes in high power broad area gain guided semiconductor lasers suffer from instabilities that can lead to self focusing of the optical modes resulting in the formation of beam filaments. The introduction of cold cavity index guiding, by means of etched holes, has been previously shown to reduce filament formation in the optical near field. In this work, a simple measurement technique is presented and utilized to characterize the behavior of local intensity fluctuations in the time domain. The use of etched holes to provide index guiding is shown to provide a significant improvement in the temporal stability of the lateral optical modes.
author_names: C Chen

Paul O Leisher

Steve Patterson

P A Crump

Yong Kwan Kim

Kent D Choquette
title: Stabilization of lateral mode transients in high power broad area semiconductor lasers
year: 2009

abstract: The spatial "rocking" is a dynamical effect converting a phase invariant oscillatory system into a phase bistable one, where the averaged phase of the system locks to one of two values differing by p. In this paper we consider theoretically the spatial rocking of irregularly operating edge emitting broad area semiconductor laser. The stabilization of the laser is realized by the injection of an optical field formed by two, coherently interfering at some angle, beams. We demonstrate that this stabilization is preserved if one or both injected beams are weakly focused, and analyze a corresponding focusing of the emitted field.
author_names: Mindaugas Radziunas

Kestutis Staliunas
title: Spatial "rocking" for improving the spatial quality of the beam of broad area semiconductor lasers
venue: Photonics Europe
year: 2012