High-power, narrow single-lobe operation from 20-element phase-locked arrays of antiguides

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Abstract
Pure in-phase-mode operation is obtained from 20/21-element AlGaAs/GaAs antiguided arrays grown by two-step metalorganic chemical vapor deposition. Oscillation of out-of-phase modes is substantially suppressed by a built-in spatial filter: two sets of noncollinear antiguides separated by a 50-μm-long laterally unguided region, corresponding to the half-Talbot distance. Design considerations for 20- vs 10-element arrays are discussed. Diffraction-limited-beam operation (i.e., 0.8° lobewidth) is obtained to 1.5×threshold (90 mW, both facets). Beams with 1.3° lobewidth (1.6×diffraction limit) are obtained at 3×threshold and 300 mW (both facets). Devices with optimized facet coatings operate in a single, 1.5°-wide lobe (i.e., 1.8×diffraction limit) at 330 mW front-facet emitted power. The main lobe contains 80–87% of the total power.