Abstract

The modulation characteristics of vertical-cavity surface-emitting lasers (SELs) are of groat interest for use in optical interconnects and high-speed wavelength-division-multiplexing arrays.¹ To date, small-signal responses have only been reported for devices with QW active regions in the GaAs^2-4 and strained InGaAs¹ material systems. At the higher output levels necessary to achieve bandwidths >10 GHz, gain saturation due to the high photon densities in the surface-emitting geometry may limit the maximum achievable modulation speed. Due to the low damping observed in edge-emitting Lasers with bulk active regions, low threshold double heterostructure (DH) devices may play an important role in future high-speed designs. We report what we believe to be the first measurements of the modulation behavior of surface-emitting lasers with bulk active regions showing thermally limited bandwidths up to 4.5 GHz. The effect of multiple transverse-mode operation in reducing the rate of bandwidth increase at higher bias levels is demonstrated.

© 1992 Optical Society of America