Abstract

Recently, we reported the fabrication and operation of GaAs heterostructure lasers with an unstable resonator (UR) and showed that the unstable resonator geometry is a promising approach for coherent high-power semiconductor lasers.¹ However, the reported lasers exhibit an external quantum efficiency considerably lower than that of Fabry-Perot lasers, and their tar-field diffraction angle is large. Considering that the output characteristics of UR semiconductor lasers can be controlled by using different cavity configurations, we designed and fabricated UR semiconductor lasers with two new geometries; the ridge waveguide unstable resonator and the confocal unstable resonator [Figs. 1(a) and (b), respectively].

© 1985 Optical Society of America