WAVELENGTH SELECTIVE OPTICAL SWITCH AND OPTICAL SIGNAL RECEIVING SYSTEM USING THE SAME

摘要

PURPOSE: To constitute the above switch in such a manner that light of a specific wavelength is outputted from another waveguide without decreasing the power of its specific wavelength even when this light is outputted from one waveguide by imparting an adequate gain to at least either of two waveguide modes. CONSTITUTION: An active layer 3 and a distributed feedback type diffraction grating 4 are included in a part of the semiconductor layer constituting the second waveguide 2. This distributed feedback type diffraction grating 4 is formed near a mode electric field where the amplitude of another waveguide mode attains 0 in such a manner that only the one waveguide mode of the two waveguide modes respectively having the central intensity in the first waveguide 1 and the second waveguide 2 receives a diffraction effect. Only the light of the prescribed wavelength is coupled from the one waveguide to the other waveguide and is outputted from the other waveguide if current is injected into the active layer of such constitution. The prescribed wavelength light receives the gain during the propagation in the other waveguide and is partly returned to the one waveguide. The uniform output without depending upon the wavelength is obtd. from the one waveguide.