Improvement of kink-free operation in InGaAs/GaAs/AlGaAs high power, ridge waveguide laser diodes

This paper demonstrates the improvement of kink-free operation in InGaAs/GaAs/AlGaAs high power, ridge waveguide laser diodes. Results show that when the thickness of the insulator layer is reduced below 200 nm and Ti/Pt/Au is used as the p-type metallization, significant absorption outside the ridge occurs as a result of the penetration of the vertical optical field into the absorptive metal layers. This effect can be used to introduce selective loss for the first order lateral mode. Hence, this study has shown that the kink-free operation can be improved by 30 to 50% in 980 nm emitting laser diodes when the thickness of the SiO₂ insulator is reduced to 50 to 75 nm.