High-speed modulation characteristics of helium-implantedzinc-diffused vertical cavity surface emitting lasers

The high-speed modulation characteristics of helium-implanted zinc-diffused vertical cavity surface emitting semiconductor lasers are measured. Devices with a nominal active region diameter of 10 and 20 μm exhibit a move-out rate of 4.5-6.5 GHz/mW^1/2 and a K factor of 0.65-0.85 ns. Maximum modulation frequency is limited by ohmic heating to approximately 5.5 GHz for 10-μm diameter lasers and to 2.7 GHz for 20-μm diameter lasers. A rolloff in the response below the relaxation oscillation frequency is observed and is explained well by a diffusion capacitance model