Single lobe operation of a 40-element laser array in an external ring laser cavity

Single lobe operation of a 40-element GaAlAs gain guided coupled stripe array emitting 500 mW cw is obtained in an external ring laser cavity. The cavity arrangement is equivalent to self-injection locking of the array by its own output, which is first spatially filtered by a single mode fiber. Diffraction-limited lobe width of 0.13° and single mode operation are demonstrated with a 90 mW single mode fiber output.