Apodizing holographic gratings for dual-wavelength operation of broad-area semiconductor lasers.
Apodizing holographic gratings are designed to have a Gaussian reflectivity profile in the -1 order and a complementary reflectivity 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 preselected wavelength separation. The results obtained with a commercial broad-area laser are presented.
Lepage
J F
JF
McCarthy
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