Injection locking and single-mode fiber coupling of a 40-element laser diode array

Abstract
Near-diffraction-limited (0.13° wide) single-lobe operation of a 40-element AlGaAs array emitting 510 mW cw is obtained by external injection locking, with 11.0 mW of injected power incident on the array. The injected and the array output beams were tilted relative to the facet normal to allow for spatial separation of the two beams and efficient coupling into a single-mode fiber; 150 mW was coupled into a 5-μm core, polarization holding fiber.