High-power laser diodes with dry-etched mirror facets and integrated monitor photodiodes

Abstract

High-power broad-area InGaAs-AlGaAs-GaAs single-quantum-well separate-confinement heterostructure (SQW-GRINSCH) lasers with dry-etched mirror facets and integrated monitor photodiodes have been investigated. A multilayer resist system has been employed as a mask for the chemically assisted ion-beam etching (CAIBE) process resulting in vertical and smooth laser facets. Thick electroplated gold layers on top of the ohmic contacts improve the heatsinking of the lasers leading to reasonable continuous-wave (CW) output powers even when the devices are mounted junction-side up. Monolithically integrated monitor photodiodes provide a linear response to the optical output powers of the laser diodes. The properties of broad-area lasers with dry-etched and cleaved facets are almost identical, Record values for the CW output powers of 2.59 W per uncoated facet and wall-plug efficiencies of more than 55% have been achieved with junction-side-down mounted devices.