THIN-FILM DESIGN FOR ENHANCED STABILITY OF OPTICALLY PUMPED VERTICAL-CAVITY SURFACE-EMITTING LASERS (VCSELS)

We have employed a novel approach to enhance the optical pump-coupling stability of vertical-cavity surface-emitting lasers (VCSELs). These structures are composed of thin-film semiconductor multilayers and are manufactured entirely by thin-film deposition. In the past, pump ligh t was coupled into VCSEL cavities through the short wavelength interfe rence notches in the reflectance spectrum. However, the steep slope an d narrow width of the notches inherently makes pump-coupling sensitive to device temperature. We have employed traditional thin-film optimiz ation to the multilayer etalon to create a low ripple, wideband pump r egion of low reflectance while maintaining cavity-mode field overlap a t the quantum wells. We demonstrate a factor of 2.5 times better stabi lity across a 35 nm spectral range.