Dry-etched-cavity pair-groove-substrate GaAs/AlGaAs multiquantum well lasers

Abstract
A fabrication technique based on reactive ion beam etching is presented for the formation of the facet mirrors on GaAs/AlGaAs lasers called pair-groove-substrate (PGS) multiquantum well lasers. Laser cavities with vertical and smooth walls are achieved with this etching technique by using a high-temperature baked photoresist mask. PGS lasers with 200-μm-long etched cavities show a low pulsed threshold current of 29 mA and a high external differential quantum efficiency of 43%. The threshold current is comparable to those of cleaved lasers. Room-temperature cw operation is easily realized in junction-up mounting.