| 摘要 |
PROBLEM TO BE SOLVED: To provide a variable optical attenuator and apparatus which can be assembled with improved accuracy in a shortened time, and facilitate control over an attenuation quantity. SOLUTION: The variable optical attenuator 10 which is provided in an area of a parallel beam 14 formed between a couple of opposite optical systems 13 and continuously attenuates the parallel beam is equipped with a shielding member 30 which is nearly in a disk-like shape and has a shielding part 31, varying in projection quantity from a center of rotation in a diameter direction and thickness in a circumferential direction, on an end surface on the circumference and a driving means 40 which rotates the shielding member 30, and varies the attenuation quantity of the parallel beam 14 by the shielding part 31 as the shielding member 30 rotates.
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