Phase-locked semiconductor laser array

Abstract
Five optically coupled narrow stripe (3.5 μm) GaAs/GaAlAs semiconductor lasers on 8‐μm centers are operated as a spatially coherent phase‐locked laser array. Output beams with less than 2° divergence are observed up to 60 mW/facet output with a quantum efficiency of greater than 25%/facet. Significant nonlinearities do not appear until well over 100 mW/facet output.