OPTICAL MODULATOR

摘要

An optical modulator for optically modulating light propagating on a three-dimensional optical waveguide (5) by applying a voltage to the light. The optical modulator comprises a three-dimensional optical waveguide (5) including at least a pair of branched optical waveguides (5c, 5d), the multiplexing portion (5e) of the branched optical waveguide and an exit portion (5f) on the downstream side of the multiplexing portion, modulation electrodes (3A, 3B, 4) for applying a signal voltage for modulating the light propagating on the three-dimensional optical waveguide (5), and primary mode optical guide waveguides (6A, 6B) for guiding primary mode light from the multiplexing portion. The thickness of the substrate is 20 µm or less at least under the modulation electrode, and operating point of the optical modulator is controlled by varying a DC bias applied to the modulation electrode based on the optical output from the guide waveguide.