Patent ID: 7010179

Claim:
A differential drive semiconductor optical modulator comprising: a differential driver circuit having first and second output terminals which can output a pair of differential signals; a transmission-line substrate having a first transmission line connected to the first output terminal, a second transmission line connected to the second output terminal, and a ground line; a first semiconductor modulator connected between the first transmission line and the ground line, mounted on the transmission-line substrate; a second semiconductor modulator connected between the second transmission line and the ground line, mounted on the transmission-line substrate, the first and second semiconductor modulators being arranged in series along a common optical axis; and a first terminal resistor connected between a terminal end of the first transmission line and the ground line, a second terminal resistor connected between a terminal end of the second transmission line and the ground line, a first inductance interposed between the first semiconductor modulator and the first terminal resistor, and a second inductance interposed between the second semiconductor modulator and the second terminal resistor, located on the transmission-line substrate.