Patent ID: 8068703

Claim:
An optical modulator comprising: an optical modulation element having a substrate with an electro-optic effect, an optical waveguide formed on the substrate, and a modulating electrode for modulating light passing through the optical waveguide; and a connection substrate, arranged outside the substrate, for supplying the optical modulation element with a microwave signal operating the optical modulation element, wherein a signal input terminal and a signal output terminal are formed on the connection substrate, an electrical circuit element for converting the microwave signal into various states is arranged in a signal line from the signal input terminal to the signal output terminal, and the signal output terminal is not located on a path through which a radiation mode of a microwave signal input to the signal input terminal propagates, as viewed from above, by bending the signal line, for suppressing the radiation mode of the microwave signal from being recombined with the signal output terminal.