Multiple vertical mode high power 975 nm diode lasers restricted to single vertical mode operation through use of optical facet coatings

A new design approach has been developed for facet coating of high power diode lasers, that is shown to preferentially suppress higher-order guided optical modes, without any degradation in device performance. Repeated optical coating of reference lasers is found to controllably transform the vertical far field from a three-peaked higher-order mode to a single-peaked fundamental mode, in good agreement with simulations. 975 nm devices with such coatings reach power conversion efficiency of 65%.