Improvement of the kink-free operation in ridge-waveguide laser diodes due to coupling of the optical field to the metal layers outside the ridge

The kink-free output power in 980-nm emitting laser diodes can be increased by 30%-50% in ridge-waveguide devices when the thickness of the oxide is decreased such that the optical field is allowed to interact with the lossy Ti-PtAu metallization outside the ridge. This provides selective loss for the first-order lateral mode and delays the onset of the beam steering associated with kinks in the power output-current characteristic. The method is very simple and can be applied for any kind of ridge-waveguide semiconductor laser diode device.