Phase-matched optical second-harmonic generation in GaN and AlN slab waveguides

Phase-matched optical second-harmonic (SH) generation was observed in GaN a nd AlN slab waveguides. Phase matching was achieved by waveguide modal disp ersion. By tuning the output wavelength of an optical parametric amplifier, several phased-matched SH peaks were observed in the visible spectrum cove ring blue to red wavelengths. The peak positions are in agreement with the values calculated using the dispersive refractive indices of the film and s ubstrate materials. (C) 1999 American Institute of Physics. [S0556-2821(99) 03904-1].