LIMITS OF THE MODULATION RESPONSE OF A SINGLE-MODE PROTON-IMPLANTED VCSEL

The limitations of the direct modulation bandwidth for proton implante d vertical-cavity lasers were explored, The measured damping factor of an optimized device, implies a possible bandwidth of up to 80 GHz, Ho wever, the intrinsic (parasitic free) carrier transport/capture time o f similar to 15 ps limits substantially the actual frequency response. The actual measured bandwidth-14.5 GHz was limited also by the emergi ng of higher lasing modes. The combined effects of shape, size and imp lantation dose should be optimized to reach the limit of the direct mo dulation of these lasers.