VARIABLE LIGHT ATTENUATOR

摘要

PROBLEM TO BE SOLVED: To provide a variable light attenuator in which problems related to temperature are eliminated in principle and the attenuation of light beam passing through an optical waveguide is controlled to be constant without being influenced by a temperature variation. SOLUTION: A positional variation detection mechanism 501 which detects the inserting position of an inserted plate 103 into the core 101 of the optical waveguide is provided, the position of the inserted plate is driven and controlled according to the detected position of the inserted palate detected by the positional variation detection mechanism. A feed back circuit is provided to detect the inserted position of the inserted plate 103 into a slit 102 on the basis of the variation in the electric capacity between an electrode 302 provided on an inserted plate driving mechanism 111 and the electrode 301 provided on an inserted plate driving mechanism supporting substrate 114, or the variation in the electric capacity between the electrode provided on the inserted plate driving mechanism and the electrode provided on a waveguide supporting substrate, and drives and controls the inserted plate driving mechanism so that the inserted plate moves to a position at which the attenuation of the light beam becomes constant on the basis of the detected position. COPYRIGHT: (C)2005,JPO&NCIPI