Low resistance intracavity-contacted oxide-aperture VCSELs

Abstract
The authors study, analytically and experimentally, the extrinsic series resistance in intracavity-contacted vertical-cavity surface-emitting lasers (VCSEL's). Low resistance, low threshold-current, intracavity-contacted VCSELs are fabricated, with resistances ranging from 355 /spl Omega/ for 4-/spl mu/m square apertures to 80 /spl Omega/ for 12-/spl mu/m square apertures and threshold voltages as low as 1.35 V. To the best of our knowledge, these are the lowest values reported for this type of VCSEL. The threshold currents range from 270 /spl mu/A for 4 /spl mu/m/spl times/4 /spl mu/m apertures to 850 /spl mu/A for 12 /spl times/12 /spl mu/m. From a comparison of the resistance as a function of oxide aperture radius, the measured data follows closely with the calculated data, demonstrating the validity of the derived expressions for series resistance.