| 摘要 |
PURPOSE:To reduce crosstalk by providing another waveguide closely to one waveguide in parallel and forming a reflecting means on the exit end surfaces of both the waveguides. CONSTITUTION:The directional coupler 51 functions as a 1st wavelength selecting element and light signal with wavelength lambda1 is lead out through a core 31; and a core 32 which propagates a light signal with wavelength l2 demultiplexed by the directional coupler 51 functions as the wavelguide A and a core 33 which is provided closely to the waveguide A in parallel functions as the waveguide B. A directional coupler 52 is provided with a reflecting film 6 as the reflecting means on one end surface side of the two parallel waveguides A and B. The light signal with the wavelength lambda2 which is propagated in the core 32 as shown by an arrow A is coupled with the core 32 through the reflecting film 6 and propagated as shown by an arrow 74. Thus, the waveguides A and B constitute the directional coupler, so respective light signals demultiplexed by the 1st wavelength selecting element 51 are projected at a sufficient distance. Consequently, the crosstalk is reduced. |
