| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical filter that has narrow spectrum half-band width. SOLUTION: This optical filter is so constituted as to convert an LP01 mode into an LP02 mode and reflect it when the LP01 mode is made incident on a fiber grating formed in a fiber core. In this case, this optical filter is used and its center wavelength is adjusted with the cycles of the fiber grating or the spectrum half-value width of the reflected light is adjusted with the light inductive reflection rate variation quantity and fiber grating length of the fiber grating. |
