| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical modulator having a large bias control voltage and being capable of ensuring a longer operation lifetime, in which a high frequency modulation signal and a DC voltage for bias control are applied together to a modulation electrode.SOLUTION: An optical modulator includes: a substrate having electro-optic effects; an optical waveguide formed on the substrate; and a modulation electrode for modulating a light wave propagating in the optical waveguide. A high frequency modulation signal and a DC bias voltage for bias control are applied together to at least a part of the modulation electrode, and at least two or more capacitors (voltage dividing capacitors) are connected in series between modulation signal supply means (a signal source and a drive driver) for supplying the high frequency modulation signal to the modulation electrode and an input part of the modulation electrode, and a potential difference generated by a DC voltage accompanying the supply of the high frequency modulation signal and the DC bias voltage is divided by the capacitors. |
