Waveguides in KNbO₃by He⁺implantation

Abstract

Abstract In a KNbO3 single domain substrate crystal a permanent multimode waveguide has been produced for the first time by implantation of 2 MeV He+ ions. Annealing is unnecessary since electronic damage is small. The irradiation flux was controlled such that no unwanted phase transitions or domain formation occured. The refractive index profile was investigated by dark line mode spectroscopy and reconstructed by a new inverse WKB procedure. The waveguiding layer has a thickness of about 3 μm, in the region directly below this layer the refractive index is decreased by more than 0.1.