5.2-5.6-µm source tunable by frequency conversion in a GaAs-based waveguide

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 micro m was achieved by variation of the waveguide temp. and one pump wavelength. IR output power ?0.12 micro W was obtained with the product of two pump powers of 7 mW2. Losses of .apprx.50 cm-1 were measured for the mid-IR radiation. These losses are attributed to surface scattering. [on SciFinder (R)