| 摘要 |
PROBLEM TO BE SOLVED: To obtain stable attenuation performance with respect to incident light of high power. SOLUTION: A variable optical attenuator 1A is provided with a shaft member 2, a servomotor 6, and a control circuit 7. The shaft member 2 has a shielding part 3 on the optical path, by which the incident light passes, and both ends of the shaft member 2 are rotatably supported via a bearing member 5 with respect to a support member 4. The servomotor 6, based on the control of the control circuit 7, rotationally drives the shaft member 2. The rotary shaft L2-L2 of the shaft member 2 is orthogonal to the optical axis L1-L1 of the incident light on a plane and is located at a position lower from the incident light optical axis L1-L1 by a prescribed amount. The shielding part 3 is moved accompanying the rotation of the shaft member 2, the incident light is intercepted by the edge 3a and the plane 3b of the shielding part 3, thereby the attenuation of the incident light varies continuously.
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