| 摘要 |
PURPOSE:To simplify the constitution of a light wave multiplex transmission device and to reduce its cost by providing a taper part halfway in a waveguide layer and providing a filter which passes a light signal with cut-off wavelength and a light receiving element which receives the signal on the waveguide layer at the taper part. CONSTITUTION:Light signals with wavelengths lambda1 and lambda2 (lambda1>lambda2) which are propagated in an optical fiber as shown by an arrow 11 are made incident on a waveguide layer 2-1; and the light signal with the wavelength lambda1 is received by a light receiving element 6 and the light signal with the wavelength lambda2 is received by a light receiving element 7. The light signal with the wavelength lambda1 is cut off at the taper part 8 and not propagated in a waveguide layer 2-2, but incident on an interference filter 4. The light signal with the wavelength lambda2, on the other hand, enters waveguide mode at this taper part 8 and is propagated in the waveguide layer 2-2 as shown by an arrow 11-3. Then, the signal reaches the 2nd taper part 9 and is bent as shown by an arrow 11-4 and emitted into an interference filter 7, so that the signal is received by the light receiving element 7. |
