| 摘要 |
PURPOSE:To provide a light sending and receiving module composed of an optical waveguide substrate with compact size and low loss. CONSTITUTION:A light sending and receiving module is provided with a light emitting element 16 to send a photosignal with lambda1 wavelength, a first optical waveguide 12 to which the sent photosignal is sent, and a second optical waveguide 11 to send the sent photosignal and at the same time to receive a photosignal. The first optical waveguide 12 and the second optical waveguide 11 have directional joining parts formed nearly as to make the length of the parts be a half of the complete joining length to the wavelength lambda1 and at the end of the directional joining parts a filter 15 which reflects the sent photosignal with lambda1 wavelength and can transmit a received photosignal with lambda2 wavelength is installed and a light receiving element 17 to receive a received photosignal is put at the position on the opposite to an optical waveguide substrate 18 while having the filter 15 between them. A wave compounding and wave dividing part 13 is put only at one site and only two optical waveguides 11, 12 are needed, so that loss of the module is lessened. Since an optical fiber 19 to be connected with the transmission line and a light emitting element 16 can be arranged on the same side relatively to the substrate 18, the module can be made compact. |
