Patent ID: 6226428
Filing Date: 2001-05-01
Classification: G02B

Abstract:
An optical circuit device comprising:a directional coupling section comprised of first and second optical waveguides and having a length n times (n is an integer of two or more) a minimum length required to completely couple light inputted to said first optical waveguide to said second optical waveguide, andat least one diffraction grating formed in said directional coupling section and having a specific reflection characteristic,wherein when input light beams having different wavelengths are input to an input side of said first optical waveguide, light having a reflection wavelength in said diffraction grating is demultiplexed/outputted to an input side of said second optical waveguide, and light beams having other wavelengths other than said reflection wavelength are outputted to an output side of said first or second optical waveguide, and when the light having the reflection wavelength in said diffraction grating is inputted through one of the output sides of said first and second optical waveguides from which the light beams having other wavelengths are not outputted, the light having the reflection wavelength inputted through the output side of said optical waveguide is multiplexed with the output light beams having other wavelengths,wherein LG20=the length of the at least one diffraction grating, L19=the length of the directional coupling section, d.PHI. is the phase difference between even and odd modes of light reflected by the at least one diffraction grating, and kc is the coupling coefficient of the directional coupling section, and wherein ##EQU1##