Title :
Gain measurements on GaAs-based quantum cascade lasers using a two-section cavity technique
Author :
Barbieri, Stefano ; Sirtori, Carlo ; Page, Hideaky ; Beck, Mattias ; Faist, Jérôme ; Nagle, Julien
Author_Institution :
Lab. Central de Recherches, Thomson-CSF, Orsay, France
fDate :
6/1/2000 12:00:00 AM
Abstract :
A two-section cavity device has been used to measure gain spectra and waveguide losses of a GaAs-based quantum cascade laser. The device operates at 8.9 /spl mu/m and optical confinement is obtained by means of Al-free cladding layers. We investigated the gain characteristics in a spectral window of /spl sim/60 meV and up to 200 K. For current densities ranging from 1 to 8 kA/cm/sup 2/, we report a constant gain coefficient of 13 cm/kA at 4 K and 6 cm/kA at 200 K. At low temperatures and for current densities above 8 kA/cm/sup 2/, we observe gain saturation which we attribute to a reduced electron injection in the active region caused by space charge effects. We report a value of 22 cm/sup -1/ for the waveguide losses in good agreement with previous measurements.
Keywords :
III-V semiconductors; current density; etching; gain measurement; gallium arsenide; laser beams; laser variables measurement; optical fabrication; optical loss measurement; optical losses; optical saturation; photolithography; quantum well lasers; ridge waveguides; space charge; waveguide lasers; 200 K; 4 K; 60 meV; 8.9 mum; Al-free cladding layers; GaAs; GaAs-based quantum cascade laser; GaAs-based quantum cascade lasers; active region; constant gain coefficient; current densities; gain characteristics; gain measurements; gain saturation; gain spectra; low temperatures; optical confinement; reduced electron injection; space charge effects; spectral window; two-section cavity device; two-section cavity technique; waveguide losses; Current density; Electrons; Gain measurement; Loss measurement; Optical devices; Optical losses; Optical saturation; Optical waveguides; Quantum cascade lasers; Temperature distribution;
Journal_Title :
Quantum Electronics, IEEE Journal of
