| 摘要 |
PROBLEM TO BE SOLVED: To provide a bias controller of a light intensity modulator, which causes little deterioration in signal of modulated light, accurately controls a bias point and has the suppressed cost as the whole of the controller. SOLUTION: The bias controller of the light intensity modulator includes: the light intensity modulator 4 having a Mach-Zehnder type optical waveguide 5; and a direct current bias control means 28 which controls direct current bias voltage applied to the light intensity modulator, the bias controller further includes: a re-incidence means which makes a portion of a light wave radiated or emitted from the exit side of the Mach-Zehnder type optical waveguide re-incident on the exit waveguide of the Mach-Zehnder type optical waveguide; a detection means 24 which detects the light wave radiated or emitted from the entrance side of the Mach-Zehnder type optical waveguide; a clock voltage application means which applies a clock voltage together with the direct current bias voltage to the light intensity modulator; and a bias control means which controls the direct current bias voltage on the basis of the detection result of the detection means. COPYRIGHT: (C)2010,JPO&INPIT |
