| 摘要 |
An optical modulation device comprises an optical modulator (102) in which the operating point is varied according to a bias voltage (Vb). A phase deviation (Pd) of an operating point from a selected optimal operating point is detected by a phase comparator (107) based on an output light (ML) of the optical modulator (102). The bias voltage (Vb) is generated within a predetermined voltage range (409) by a DC amplifier (110) so as to reduce the phase deviation (Pd). A reset circuit (109) resets the bias voltage (Vb) at the ground voltage associated with the selected optimal operating point when the optical modulator (102) is powered up and passes the bias voltage to the optical modulator at all other times. <IMAGE> |
