| 摘要 |
PURPOSE:To obtain the device which allows the easy formation to a small size by providing a channel waveguide in which a basic wave propagates and a planar slab waveguide for taking out the second higher harmonic wave from the basic wave and satisfying specific conditions. CONSTITUTION:A nonlinear optical thin film 2 which constitutes the slab waveguide is formed on a glass substrate 1. This thin film 2 is partly molded to a band-shaped ridge shape which constitutes the channel waveguide 3. The basic wave 4 propagating in the waveguide 3 generates the second higher harmonic wave by the secondary nonlinear effect of the medium. The Cerenkov radiation of the second higher harmonic wave to the slab waveguide is possible under the conditions under which the basic wave propagates in the channel waveguide and the phase speed of the second higher harmonic wave is higher than the phase speed of the slab waveguide in the side part, i.e., when equation I is satisfied. The limitation on the kinds and thicknesses of the substrate is relieved in this way and the formation of the compact device is allowed. |
