| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To obtain a high cutoff quantity in excess of 40 dB in a wide band exceeding 1 nm, with a simple constitution. <P>SOLUTION: In an FBG section 40 that performs high cutoff filtering against optical input in excess of 40 dB in a wide band exceeding 1 nm, a photo-sensitive material having a phtosensitivity against ultraviolet rays is added in the region of a cladding 42 so as to form the chirped Bragg grating same as that in the region of the core 41. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
