| 摘要 |
PROBLEM TO BE SOLVED: To efficiently suppress transmission distortion with simple constitution, without reproducing transmission information by utilizing the interference of light obtained through plural optical paths. SOLUTION: The output of a light amplifier 52 supplied with pulse light modulated, corresponding to luminance pulse signals, is connected to the optical input of an arm 541 provided in a Mach-Zehnder interference device (MK) 54 through a control part 53. Also, the output of a light source 55 is connected to the input of the MK 54, and interference light is obtained in the output of the MK 54. Also, a bias voltage is applied to the control input of the other arm 542 of the MK 54. Then, the bias voltage is set beforehand to a value for which luminance to be the reference of the pulse light matches with the minimum point of a trigonometric function. Then, the control part 53 monitors the level of the pulse light and varies the gain of the light amplifier 52 in the direction of absorption for the fluctuation portion of the level. |
