Phase front measurements of AlGaAs 830 nm phase-locked lasers with a real-refractive-index waveguide

A phase-locked laser array with refractive-index waveguides and emitting a low phase-aberration beam is described. A fundamental supermode operation of an evanescent-coupled three-element laser array which emits up to 200 mW in a single diffraction-limited beam is achieved. The full beam angle at the half-power point is 3.2° in the direction of parallel to the p-n junction. This phase aberration is less than λ/14 from 50 to 150 mW. The extremely low phase aberration (0.022λ) is measured at 50 mW.