| 摘要 |
PURPOSE:To determine a multiple demultiplexing characteristic by only a filter characteristic as a whole, irrespective of the distribution of a coupling coefficient by separating a mechanism for selecting the wavelength and a directional coupler. CONSTITUTION:A multiple signal which is brought to four-wave multiplexing passes through an optical waveguide 11 and made incident on an input terminal 14 of a 3dB demultiplexing and coupling circuit 13, allowed to branch into the power of half each by the circuit 13, and thereafter, outputted from output terminals 16, 17, respectively. The length of optical waveguides 18, 19 on which these output light beams are made incident is almost the same, and on the way thereof, the first and the second waveguide type diffraction gratings 20, 21 having almost the same reflection/transmission characteristic, respectively are formed at positions being roughly equal from the output terminals 16, 17. Also, injection electrodes 46-49 are used for injecting a current to active layer areas 31-34 provided before and behind these diffraction gratings 20, 21. In such a way, various diffraction gratings can be applied. |
