| 摘要 |
PROBLEM TO BE SOLVED: To utilize cut-off light as well as a function of cutting off and attenuating light.SOLUTION: An variable optical attenuator includes a shutter plate 201 which is disposed substantially orthogonally to an optical path of an optical fiber 11, a moving mechanism 202 which slides the shutter plate 201 substantially orthogonally to insert it into the optical path, and a photodiode 203 which is provided on the shutter plate 201, and utilizes light, cut off by the shutter plate 201, of light transmitted through the optical fiber 11. |
