| 摘要 |
PROBLEM TO BE SOLVED: To obtain flexibility in positioning of an external resonator type optical system and shorten the length of the external resonator. SOLUTION: The turning axis R of a mirror 25 is positioned so that it is included in a plane H1 obtained by extending the diffraction plane of a diffraction grating 24 and displaced from the plane H3 obtained by extending the reflection plane of the mirror 25. At the same time, the following relationship is obtained: r=(L1+L2)/sinαor r=(L1-L2)/sinαwhere the distance (r) for the turning center of the mirror 25 to the incident point G of the light made incident to the diffraction grating 24, the effective optical distance L1 from the incident point G to a semiconductor laser 22, the distance L2 from the turning center of the mirror 25 to the plane H3 obtained by extending the reflection plane of the mirror 25 and the incident angleαof the light to the diffraction grating 24.
|
