Optimal designs are developed for large optical cavity (LOC)-type GaAs-distributed Bragg reflection lasers. Cavity and reflector lengths are determined which allow single-mode single-ended operation over a CW optical-output power range of 5-50 mW. Assuming an internal quantum efficiency of 90 percent, external quantum efficiencies for the optimized structures are found to range from 14.1 percent (for 5-mW output) to 57.8 percent (for 50-mW output). Threshold current densities are found to remain less than

over the entire optical output range considered.