Laser diodes formed on a common substrate with layers of suitable thickness and refractive indices produce output beams that are coherently coupled. A phase mask can be situated to produce phase differences in one or more of the output beams to produce a common wavefront phase. The phase-corrected beams propagate with reduced angular divergence than conventional lasers that are not coherently coupled, and the coherently coupled laser diodes can provide higher beam brightness, enhanced beam parameter product, and superior power coupled into doped fibers in fiber lasers.