| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a device for forming a long-cycle grating in an optical fiber so that a polarized-wave dependent (polarized-light dependent) loss is nearly removed. SOLUTION: In this invention, a radiation source, a base having a V-shaped groove formed, and an optical fiber installed in the groove are provided. The surface of the groove are inclined at 60 deg. to the propagation direction of radiation which is mode incident on the optical fiber from the radiation source and have high reflectivity characteristics to the radiation. In the core of the optical fiber, is a grating with radiation which is mode incident directly from the radiation source and radiation which is radiation from the radiation source and then reflected by the flank of the groove, is formed. |
