| 摘要 |
PROBLEM TO BE SOLVED: To male easily formable a core layer and clad layers by a photobleaching action by successively forming an upper clad having a low refractive index, a UV-cut layer or the like on a core layer and on side-face clad layers. SOLUTION: A buffer layer 2 having a low refractive index nb is formed on a Si substrate 1, and a core layer 4 having a high refractive index nw (nw>nb) and almost square cross section subjected to photobleaching is formed thereon. Then clad layers 3-1 and 3-2 subjected to photobleaching and having a low refractive index ncs (ncs<nw) are formed on both sides of the core layer 4. Further a clad layer 5 having a low refractive index ncu (ncu<nw) and a UV-cut layer 6 are successively formed on the core layer 4 and the clad layers 3-1, 3-2. By forming the UV-cut layer 6 on the clad layer 5, changes in the refractive indices of the photobleached core layer 4 and clad layers 3-1, 3-2 due to UV rays from sun rays and a lamp can be suppressed. |
