High-speed characteristics of vertical cavity surface emitting lasers and resonant-cavity-enhanced photodetectors based on intracavity-contacted structure

Abstract

We fabricated vertical cavity surface emitting lasers (VCSELs) and resonant-cavity-enhanced photodetectors (RCE-PDs) with GaAs/AlGaAs distributed Bragg reflectors (DBRs), operating at lambda similar to 980 nm, based on an intracavity-contacted structure. The top-DBR mesa diameter of the VCSELs was optimized to 18 mu m in terms of slope efficiency, differential series resistance, and 3 dB bandwidth. For VCSELs with an oxide aperture of 4.5 mu m and a top-DBR mesa diameter of 18 mu m, the threshold current was about 1.2mA, exhibiting maximum output power of similar to 3.49mW (at 20 degrees C) with good uniformity. The effect of the overetching in the outermost layer of RCE-PDs on the device performance was also investigated. For RCE-PDs based on the VCSEL structure, a peak responsivity of 0.44A/W (at lambda similar to 979.7 nm) with a spectral width of similar to 3nm and a dark current of 68 pA under a bias voltage of -5V at 20 degrees C was obtained. The maximum 3 dB bandwidths of similar to 11.5 GHz with a modulation current efficiency factor of 5.6GHz/mA(1/2) at -7mA and 9GHz at -7V were achieved for VCSELs and RCE-PDs, respectively. (C) 2009 Optical Society of America