| 摘要 |
PROBLEM TO BE SOLVED: To provide an inclined Bragg grating optical waveguide part for adjusting spectral response of a transmission filter in an optical waveguide or in an optical fiber. SOLUTION: In order to smooth response of a filter modulated by combination with many kinds of clad modes, a pitch of a Bragg grating is changed linearly along the length of the filter. In order to fit an attenuation band to a necessary band, a clad of an optical fiber is doped with photosensitive material, to thereby form a grating also in the clad. The photosensitivity of the clad is advantageously larger than the photosensitivity of a core with the ratio of about 5:1. |
