| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical filter of new constitution which can control and adjust transmission characteristics. SOLUTION: An optical fiber 1 has a grating part 2 formed and the grating part 2 is fixed to a support plate 3 at an X and a Y point while curved to a radius R0 of curvature. An optical filter 10 varies in transmission characteristic with the radius R, of curvature of the grating part 2. As the temperature rises, the aluminum-made support plate 3 expands to increase the distance between the support points X and Y, the shape varies from an arc A0 to an arc A1 since the overall length of the arc A0 is invariable, and the radius of curvature of the grating part 2 varies from R0 to R0+ΔR. Spectrum variation due to the temperature variation of the grating part 2 is compensated by making use of the resulting transmission characteristic variation. When the temperature falls, the arc becomes an arc A2 and the spectrum variation is similarly compensated. |
