2ND-HARMONIC GENERATION WITH A HIGH-INDEX-CLAD WAVE-GUIDE

Theoretical and experimental analyses of second-harmonic generation (S HG) with a high-index-clad waveguide are reported. It was found that c onfinement of the propagation modes and the overlap between the fields of fundamental and second-harmonic waves could be increased in this w aveguide. This structure was achieved in an x-cut MgO:LiNbO3 quasi-pha se-matched (QPM) waveguide by use of Nb2O5 as a cladding layer. With t he QPM SHG device, harmonic blue light of 5.5 mW at the 434-nm wavelen gth was generated with a normalized conversion efficiency of 1200%/W c m(2). (C) 1997 Optical Society of America.