| 摘要 |
PURPOSE:To improve the reliability of detection and to improve the productivity of working and the reproducibility of quality by making the width of an optical waveguide formed on a substrate larger nearby a part including an exposure part than at an incidence terminal, and also providing a tapered waveguide area which increases in width gradually between both parts. CONSTITUTION:The optical waveguide 12 has a larger refractive index than other parts of the substrate and consists of incidence and projection paths 12A and 12B, a tapered path 12C, and an expanded path 12D. Optical fibers 15A and 15B are connected to end surfaces of the incidence and projection paths 12A and 12B respectively; and the other end of the incidence-side optical fiber 15A is connected to a light source and the other end part of the projection-side optical fiber 15B is connected to a photodetector. The tapered path 12C extends from the tips of the incidence and projection paths 12A and 12B and is increased in sectional diameter linearly in the axial direction, and the diameter ratio between the entrance end and exit end is increased by, for example, about three times. |
