Surface-emitting microlasers for photonic switching and interchip connections

Abstract

Vertical-cavity electrically pumped surface-emitting microlasers are formed on GaAs substrates at densities greater than two million per square centimeter. Two wafers were grown with ln_(0.2)Ga_(0.8)As active material composing three 80 Å thick quantum wells in one and a single quantum well (SQW) 100 Å thick in the other. Lasing was seen in devices as small as 1 .5 µm diameter with <0.05 µm^3 active material. SQW microlasers 5 x 5 µm square had room-temperature cw current thresholds as low as 1.5 mA with 983 nm output wavelength. 10 x 10 µm square SQW microlasers were modulated by a pseudorandom bit generator at 1 Gb/s with less than 10^(-10) bit error rate. Pulsed output >170 mW was obtained from a 100 µm square device. The laser output passes through the nominally transparent substrate and out its back side, a configuration well suited for micro-optic integration and photonic switching and interchip connections.