Size-dependent output power saturation of vertical-cavity surface-emitting laser diodes

We demonstrate efficient vertical-cavity surface-emitting laser diodes with high output power levels. Improved output power in these pillar-etched devices is achieved through a 60% lower thermal resistance by using a 15-μm-thick Au-plated heat spreading layer on the top surface with a size of 300×300 μm². The maximum continous wave output power increases almost linearly with laser diameter, before it saturates at 42 mW for an unmounted Au-plated device of 64-μm diameter. A simple analytical model describes the laser output characteristics and the size-dependent saturation behavior of the maximum output power.