High power with high efficiency in a narrow single‐lobed beam from a diode laser array in an external cavity

High output power (700 mW) in a nearly diffraction‐limited (0.7°) single‐lobed nonsteering output beam is obtained from a gain‐guided diode laser array in a novel, easily fabricated external cavity configuration. The laser output beam is collimated in both lateral and vertical directions. Differential quantum efficiency as high as 70% has been measured along with excellent linearity of the optical power versus current characteristic. The power and efficiency are the highest reported for a coupled‐stripe laser array emitting a narrow single‐lobed beam.