| 摘要 |
PROBLEM TO BE SOLVED: To obtain a high-isolation optical fiber type optical component which has cladding-mode coupling loss suppressed. SOLUTION: A uni-modal type optical fiber 1 which is formed by covering a core 2 with a cladding 5 and has a refractive index distribution in an α-power profile shape is provided with the formation part of a fiber grating, where the refractive index of the core 2 varies periodically along an optical axis Z of the optical fiber, and α is 0.5. The cladding mode coupling loss is suppressed by making small the difference between the refractive index variation and propagation mode variation at the border part between the core 2 and the cladding 5 of the optical fiber 1, and when light transmission loss generated in at an about 1,520 nm wavelength band when the light transmission stopping wavelength band by the formation part 6 of the fiber grating is set to about 1,640 to 1,660 nm is suppressed to make small the light transmission loss in the use wavelength band (about 1,550 nm band) of the optical fiber 1. |
