Square- and racetrack-lasers as active components for monolithically integrated optoelectronic devices

Deeply etched square and rectangular racetrack lasers with diameters from 200 μm down to 30 μm were fabricated by electron cyclotron resonance reactive ion etching. All devices were operated in continuous-wave mode at room temperature. Threshold currents as low as 30 mA for a square laser with 30 μm diameter were achieved. For the smallest devices with 30 μm diameter a free spectral range of 6.2 nm could be obtained equivalent to a channel distance of 760 GHz. Racetrack lasers with a 50 μm extension length show output powers up to 2.3 mW from one facet, threshold currents between 22 and 60 mA and side mode suppression ratios of 35 dB.