Lateral mode stabilization of diode lasers by means of apertured facet reflectors

We report the design, fabrication, and testing of an apertured facet reflector for a GaAs/GaAlAs room temperature CW diode laser. The reflector, composed of Al
2
O
3
, Si, Te, and Al
2
O
3
layers with the Te ablated by the laser beam itself at the mode center, has a higher reflectivity at its center compared to the unablated surrounding region. This nonuniform reflectivity acts to stabilize laterally the fundamental mode and substantially increase the "kink" level. Specifically, the "kink" level of a large optical cavity (LOC) heterostructure laser with an 8 μm wide stripe was increased from ≈ 10 mW before coating to above 30 mW by the addition of the apertured reflector.