Supermode control and phase front measurements of phase‐locked offset‐coupled laser arrays with a large optical waveguide structure

Phase‐locked array lasers with large optical waveguide structures are demonstrated. The refractive index guides of each laser are evanescently coupled with and without offset‐coupling structure. An evanescently coupled three‐element laser array without offset coupling regions emits up to 200 mW and an offset‐coupled laser array with a 4/5 element emits up to 150 mW under pulsed operation. Both laser arrays emit with all elements in‐phase locked and produce a single narrow far‐field lobe. The full widths at half maximum of the three‐element and 4/5‐element laser arrays are 5° and 2.5°, respectively. In phase measurements of the lobe of the 4/5‐element laser array, we find that the root‐mean‐square aberration is less than 0.11λ under pulsed operation. This phase aberration is constant with varying power from 75 to 150 mW.