| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical device which can suppresses changes in the center wavelength of reflection with temperature due to insufficient temperature compensation characteristics for a diffraction grating by a substrate. SOLUTION: The optical device 10 is equipped with an optical fiber 4 having a diffraction grating 6 formed, and the optical fiber 4 is adhered and fixed to the substrate 1 with a second adhesive 5. The substrate 1 consists of two first substrates 1a and a second substrate 1b which is disposed between the first substrates 1a and on which the optical fiber 4 is adhered and fixed. A recoat layer 7 is formed around the diffraction grating 6. The coefficient of thermal expansion of the recoat layer 7 is controlled to decrease more in the temperature ranges of from -50 deg.C to 0 deg.C and from 50 deg.C to 100 deg.C than in the temperature range from 0 to 50 deg.C, and in the temperature ranges of from -50 deg.C to 0 deg. and 50 deg.C to 100 deg.C, the apparent coefficient of thermal expansion in the region of the substrate 1 between fixed parts of the optical fiber 4 is higher than the specified coefficient of thermal expansion (coefficient of thermal expansion in the temperature range from 0 deg.C to 50 deg.C) for the temperature compensation of the diffraction grating 6. |
