Lateral beam collimation of a phased array semiconductor laser

The lateral near-field and far-field radiation patterns of a phase-locked array of gain-guided semiconductor injection lasers are studied. These lasers exhibit a lateral far-field beam divergence full width at half-maximum (FWHM) of 1.5° up to 200 mW of output power per facet. Greater than 60% of the laser output power is concentrated in a low divergence beam at this high optical power. Catastrophic mirror degradation of the laser occurs at ≊250–270 mW cw per facet.