OPTICAL WAVELENGTH CONVERSION ELEMENT, SHORT WAVELENGTH LASER BEAM SOURCE USING THE SAME, OPTICAL INFORMATION PROCESSOR USING THIS SHORT WAVELENGTH LASER BEAM SOURCE AND PRODUCTION OF OPTICAL WAVELENGTH CONVERSION ELEMENT

摘要

PURPOSE:To improve the efficiency of conversion and to stabilize the higher harmonic wave to be emitted by providing a nonlinear deterioration layer or reinversion layer on the surface of a nonlinear optical crystal formed with periodic polarization inversion layers and making conversion to a higher mode. CONSTITUTION:An optical waveguide 2 and the polarization inversion layer 3 are formed on an LiTaO3 substrate 1 which is a nonlinear optical crystal. The nonlinear deterioration layer 5 is formed by a proton exchange on the LiTaO3 substrate 1. An incident basic wave P1 on the optical waveguide 2 is converted in the optical waveguide 2 to the higher harmonic wave P2. The nonlinear deterioration layer or the reinversion layer is provided on the surface of the nonlinear optical crystal, by which the negation of the electric fields of the +E side and -E side of the TM10 mode of the higher harmonic P2 is prevented and the TM10 mode is easily generated with high efficiency. The influence that the basic wave P1 receives is extremely small and the optical waveguide element having such constitution can drastically decrease the fluctuations by a light damage while the high higher harmonic output is maintained. The stable higher harmonic output is thus obtd.