Short cavity GaAs/AlGaAs multiquantum well lasers by dry etching

A reactive ion beam etching method with Cl2 plasma is applied to fabricate short cavity GaAs/AlGaAs multiquantum well lasers grown by molecular beam epitaxy. Threshold currents as low as 38 mA are achieved for the 20‐μm‐long cavity lasers. The very short cavity lasers show single longitudinal mode operation under pulsed conditions. Cavity length dependence of the threshold current is also investigated for the dry‐etched lasers with cavity lengths varying from 20 to 500 μm.