Title :
Influence of DX centers on the performance of unipolar semiconductor lasers based on GaAs-Al/sub x/Ga/sub 1-x/As
Author :
Sirtori, Carlo ; Barbieri, Stefano ; Kruck, Peter ; Piazza, Vincenzo ; Beck, Mattias ; Faist, Jéerôme ; Oesterle, Ursula ; Collot, Philippe ; Nagle, Julien
Author_Institution :
Lab. Central de Recherches, Thomson-CSF, Orsay, France
Abstract :
Optical and electrical characteristics of quantum cascade lasers, made in the GaAs-Al/sub x/Ga/sub 1-x/As material system, show persistent changes at low temperatures, when devices are illuminated with an external white light. The magnitude of the effect is a function of the exposure time and finally saturates. The induced variation on the threshold current density of the lasers is more than 30%. This effect is related to the presence of deep donors (DX centers) in the high aluminum content AlGaAs cladding layers, which under illumination release electrons, thus increasing waveguide losses. By analyzing the light induced variations of the optical characteristics we were able to deduce the waveguide losses of our devices.
Keywords :
III-V semiconductors; aluminium compounds; deep levels; electron traps; gallium arsenide; laser beams; optical losses; semiconductor lasers; waveguide lasers; AlGaAs cladding layers; DX centers; GaAs-Al/sub x/Ga/sub 1-x/As laser; GaAs-AlGaAs; deep donors; electrical characteristics; electron release; exposure time; external white light; illumination; light induced variations; optical characteristics; quantum cascade lasers; threshold current density; unipolar semiconductor lasers; waveguide losses; Electric variables; Optical devices; Optical losses; Optical materials; Optical saturation; Optical waveguides; Quantum cascade lasers; Temperature; Threshold current; Waveguide lasers;
Journal_Title :
Photonics Technology Letters, IEEE
