5.2-5.6-MU-M SOURCE TUNABLE BY FREQUENCY-CONVERSION IN A GAAS-BASED WAVE-GUIDE

A tunable mid-IR source obtained by difference-frequency generation is demonstrated in a selectively oxidized GaAs-AlAs multilayer waveguide . We designed the waveguide to present the required form birefringence for phase matching of the nonlinear interaction. We took special care to lower losses for the mid-IR radiation. IR tunability from 5.2 to 5 .6 mu m was achieved by variation of the waveguide temperature and one pump wavelength. IR output power as great as 0.12 mu W was obtained w ith the product of two pump powers of 7 mW(2). Losses of similar to 50 cm(-1) were measured for the mid-IR radiation. These losses are attri buted to surface scattering. (C) 1998 Optical Society of America.