| 摘要 |
PURPOSE:To raise the detection sensitivity by increasing an optical path length, and also, to make the whole device small in size, by providing a reflecting body on the end part of an optical fiber, in a sensor for utilizing an evanescent wave of the fiber. CONSTITUTION:A single optical waveguide 11 is embedded into a transparent substrate 10, and on its upper part, a light absorbing layer 12 an a hydrogen adsorbing layer 13 is laminated and formed. The hydrogen adsorbing layer 13 consists of a substance for adsorbing and dissociating a hydrogen gas and generating an electron and a proton, and the light absorbing layer 12 consists of a substance whose light absorption coefficient is varied by receiving said electron and proton. On an end face 11A of the optical waveguide 11 which is exposed on one end face 10A of the substrate 10, a reflecting body 14 is made to adhere closely and provided. To the other end face 11B of the optical waveguide 11, an optical fiber 15 used for both an input and an output is connected optically. When transmission light is made incident on the inside of the optical waveguide 11 through the optical fiber 15, it is propagated through the inside of the optical waveguide 11, and thereafter, the propagation light is reflected as to its whole quantity by the reflecting body 14 of the other end, fed back again through the optical waveguide 11 and emitted to the optical fiber 15. |
