| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical device which has stable transmission characteristics even in the case of causing temperature variation. SOLUTION: In the optical device including birefringent materials 131 to 133, etc., the birefringent materials 131 to 133 expand and shrink respectively depending upon temperature variation ΔT and their refractive indexes ne and no vary in value. Further, expanding and shrink members 141 and 142 expand and shrink according to the temperature variation ΔT and the birefringent materials 131 and 132 move along a (y) axis respectively to vary the length of the optical path. This optical device can have a small absolute value of phase shift δ(ΔT) and stable transmission characteristics even if temperature variation occurs. |
