| 摘要 |
PURPOSE:To eliminate the need for optical axis adjustment and provide a small filter of sharp rise by making use of the optical loss of a single mode waveguide of different radii of curvature or multiple waveguides of the same radius of curvature. CONSTITUTION:The incident light to a single mode optical guide 1 with an external layer is bisected to the guide light by the core part 4 and the radiation light reflecting at the boundary 6 with the external layer of the clad 5 of a refractive index n2 smaller than that of the core part 4 and a half-amplitude level (b) by the bent parts whose radii of curvature R1 thru R3 become subsequently smaller. When the conditions of the formulas I, II wherein the phase difference of the radiation light and guide mode becomes N(integer) times of 2pi are satisfied, coupling of the radiation light and guide light becomes maximum and the guide light is converted to the radiation light, which is then radiated to the outside from the reflection point of the boundary 6, thus the light loss of the guide light becomes large. (In the formulas beta : the phase constant of the guide mode, K : the number of light waves of free space) |
