Apodizing holographic gratings for dual-wavelength operation of broad-area semiconductor lasers

摘要

Apodizing holographic gratings are designed to have a Gaussian refiectivity profile in the - 1 order and a complementary refiectivity profile in the specular (0) order. They are obtained by the interference of two Gaussian beams on a glass plate covered with a photoresist. These gratings are intended to be used as the coupler of the external cavity of a broad-area semiconductor laser. When the grating is oriented to get the -1 order counterpropagating with respect to the incident beam, single-longitudinal- and single-lateral-mode operation is obtained. We report on the fabrication technique of an apodizing holographic grating designed to allow lasing on two wavelengths simultaneously, with a presented wavelength separation. The results obtained with a commercial broad-area laser are presented. # 1998 Optical Society of America OCIS codes: 050.2770, 090.2890, 140.2020, 140.3570, 140.5960, 220.1230.