Title :
Time-resolved nonlinear absorption modulation in GaAs/AlGaAs multiple-quantum-well waveguides at 1.06 mu m
Author :
Laughton, F.R. ; Marsh, J.H. ; Button, C.
Author_Institution :
Dept. of Electron. & Electr. Eng., Glasgow Univ., UK
Abstract :
Time-resolved nonlinear absorption modulation due to two-photon absorption (TPA) and free carrier absorption (FCA) was demonstrated in GaAs/AlGaAs waveguides at 1.06 mu m. For a peak input intensity of 4.5*10/sup 11/ Wm/sup -2/, there was a maximum absorption modulation of 35%. This was caused by TPA, so that the recovery time was limited by the laser pulsewidth alone. At a peak input intensity of 1.5*10/sup 12/ Wm/sup -2/, a 65% absorption modulation was observed. This consisted of two components: an instantaneous effect due to TPA and also a slower component, attributed to FCA, whose recovery time was limited by the carrier lifetime. A theoretical model was also derived which provided a good fit to the experimental data.<>
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; high-speed optical techniques; integrated optics; light absorption; nonlinear optics; optical modulation; optical pumping; optical waveguides; 1.06 micron; GaAs-AlGaAs; IR; MQW; MQW waveguides; carrier lifetime; free carrier absorption; integrated optics; laser pulsewidth; multiple-quantum-well waveguides; optical pumping; peak input intensity; recovery time; semiconductors; time-resolved nonlinear absorption modulation; two-photon absorption; Absorption; Electron optics; Gallium arsenide; Intensity modulation; Nonlinear optics; Optical coupling; Optical crosstalk; Optical modulation; Optical waveguides; Quantum well devices;
Journal_Title :
Photonics Technology Letters, IEEE
