| 摘要 |
PROBLEM TO BE SOLVED: To provide a small temperature compensating optical fiber black grating usable even when a grating part is long by setting a linear expansion coefficient of a large annular ring smaller than a linear expansion coefficient of a small annular ring, fitting the outer periphery of the small annular ring in close contact to the inner periphery of the large annular ring, forming an annular groove in the small annular ring, and fixing a black grating part to the annular groove. SOLUTION: This temperature compensating optical fiber black grating has a small annular ring 1 having an inside diameter ofϕ1 and an outside diameter ofϕ2 and a large annular ring 2 having an inside diameter ofϕ2 and an outside diameterϕ3. Both the small annular ring 1 and the large annular ring 2 have a ring shape having an annular ring central part hollowed out in a concentrically circular shape. The outer periphery of the small annular ring 1 is fitted in close contact to the inner periphery of the large annular ring 2 to form a double ring structure of the small annular ring 1 and the large annular ring 2. A linear expansion coefficient of a material of the large annular ring 2 is set smaller than a linear expansion coefficient of a material of the small annular ring 1. An annular groove 3 being a concentrically circular shape with the ring is formed on an annular surface of the small annular ring 1. A straight line-shaped groove 4 is arranged so that a part of the groove has a common part with a part of a groove of the annular groove 3. |
