200 mW at 488 nm From a ppMgO:LN Ridge Waveguide by Frequency Doubling of a Laser Diode Module

We report on second-harmonic generation in a single-pass bench top configuration using a MgO-doped periodically poled LiNbO₃ ridge waveguide (RW) and a hybrid integrated master oscillator power amplifier laser module at 976 nm. A coupling efficiency into the crystal RW of 66% was realized and 200 mW of continuous-wave radiation at 488 nm at room temperature were reached. A conversion efficiency of 43% with regard to the coupled near-infrared radiation was obtained. The experimental results agreed well with simulations including material inhomogeneities, higher optical absorption, and thermal effects.