External cavity coupling and phase locking of gallium arsenide injection lasers

The techniques involved in phase locking large multi-element junction laser arrays will be described. Specific mention is given to external cavity coupling, laser uniformity, physical dimensions, and array configuration. As a result, it has been found that a far more ideal beam pattern can be obtained from large diffraction-limited diodes than from a linear array of small ones. A coupled five-element array of 25-mil-wide units operated at-30°C has emitted 19 watts of peak power in a set of common modes.