| 摘要 |
PURPOSE:To obtain the optical ring filter which is easily mass-produced and has excellent frequency selectivity. CONSTITUTION:A ring light guide 2 and plural input/output light guides 3 and 4 which extend while directional coupling parts 5A and 5B are formed nearby the ring light guide 2 in parallel are formed on the same substrate. Input/output ports 32 and 33, and 42 and 43 at the respective end parts of the input/output light guides 3 and 4 are tapered gradually increasing in sectional area toward the light guide ends, so a large diameter optical fiber can be connected. The input/output light guides 3 and 4 can be formed having the same large specific refractive index difference with the ring light guide 2, so they can be formed in the same process with the light guide 2 and the mass-production efficiency is improved. |
