| 摘要 |
PURPOSE:To easily control condensing of exit light, etc., by constituting an element on a substrate having a nonlinear optical effect in such a manner that one side face of a channel waveguide comes into contact with a slab waveguide and the other side face comes into contact with a layer having the refractive index lower than the refractive index of the slab waveguide. CONSTITUTION:This element is constituted of the 1st substrate 1 which has the nonlinear optical effect and the 1st refractive index n1, the slab waveguide 2 which is formed on this substrate and has the 2nd refractive index n2, the channel waveguide 3 which has the 3rd refractive index n3 and the low- refractive index layer 4 which has the 4th refractive index n4. The refractive indices n1-n4 are so determined that the relations n3>n2>n1>n4>=1 are maintained therebetween to couple the second harmonic waves of the incident light on the channel waveguide 3 to the slab waveguide light. The second harmonic waves are, therefore, transversely Cerencov-radiated and are coupled to the slab waveguide mode in the slab waveguide 2. The exist light is thereby made into the guided light propagated in the slab waveguide 2 and is confined in one direction, by which the light control such as condensing is enabled. |
