| 摘要 |
<P>PROBLEM TO BE SOLVED: To stabilize ABC control (Auto Bias Control) in an optical modulation device. <P>SOLUTION: In an optical modulation device 200, a driver 201 applies a drive signal based on a data signal to a modulation unit 203, the modulation unit 203 modulates light input from an LD 202 by the drive signal, and a bias control unit 208 calculates a bias voltage value so as to make an f0 element closer to 0(zero), according to a detection result in a synchronization detection unit 207, and supplies a bias voltage of the calculated voltage value to the modulation unit 203. The bias control unit 208 stops ABC control when the data signal is in a state different from a predefined state during the ABC control, and, after the stop of the ABC control, restarts the ABC control using, as an initial value, the bias voltage value calculated before the stop of the ABC control. <P>COPYRIGHT: (C)2013,JPO&INPIT |
