| 摘要 |
PROBLEM TO BE SOLVED: To completely perform the transfer of coupling/branching in an optical coupler/branching filter without receiving any restriction to wavelengths. SOLUTION: Since a photonic crystal body 9 which inhibits the propagation of signal light S1 in the wavelength region corresponding to a short wavelength of coupling or branching signal light S1, S2 is provided between coupling parts 6, 16 of two optical waveguides 2, 3, the transfer of non-coupling or non- branching optical signal S1 to the other optical waveguide 3 is eliminated, the coupling parts 6, 16 are formed so as to maximize a coupling ratio transferring the coupling or branching signal light S2 to the other optical waveguide 3, and complete coupling or branching is performed. Also, since the effect of the photonic crystal body 9 is not reduced with lapse of time, the high coupling ratio is held in a constant, and complete coupling or branching is performed by one coupler. |
