| 摘要 |
Abnormal losses outside a reflection band attributable to a mismatch of core field diameters are suppressed. A photo-sensitive fiber comprising a core 1 and a cladding having a cladding inner layer and a cladding outer layer formed in this order around the core, in which at least the core is photo-sensitive to form a grating. The core and cladding inner layer include a photo-sensitive dopant for increasing the refractive index. The core additionally includes a first non-photo-sensitive dopant for increasing the refractive index and the cladding inner layer additionally includes a second non-photo-sensitive dopant for creasing the refractive index. |
