| 摘要 |
PURPOSE:To reduce the polarization dependency of diffracted light by providing a means which rotates the polarization of a light beam on an optical axis. CONSTITUTION:The polarization rotating means 90 is provided on the optical axis between an acoustooptic element and a converging rod lens. Then YIG single crystal 100 which is a Faraday rotator having AR coats 110 and 111 on both end surfaces of the means 90 is inserted into and fixed in a coil 120. The crystal 100 is about 4mm thick and linear polarized light having an optional angle is obtained according to an applied voltage. A light beam which is emitted from a single-mode fiber and passed through the acoustooptic element is incident on the means 90. The voltage applied to the coil 120 is varied with time and then linear polarized light which varies correspondingly is projected from the 2nd single mode fiber. Therefore, linear polarized light beams having all angles of polarization are present nearly on an average, so the polarization dependency of the diffracted light is reducible.
|
