Blue-light second-harmonic generation in ion-implanted KNbO3 channel waveguides of new design

Abstract

We report phase-matched second-harmonic generation in KNbO3 channel waveguides. The guides were fabricated by one single homogeneous He+ ion irradiation and specially structured photoresist on the KNbO3 crystals serving as an implantation mask. The mask enabled the formation of channel guides with a trapezoidal-shaped cross section providing simultaneous confinement of both TE and TM modes. 2.6 mW second-harmonic blue-light at 441 nm was generated in a 5.8-mm-long guide for an incident fundamental power of 280 mW.