TRAVELLING WAVE ELECTRODE TYPE OPTICAL MODULATOR

摘要

PROBLEM TO BE SOLVED: To provide an optical modulator that has a travelling wave electrode enabling an impedance matching condition and a velocity matching condition to be satisfied together.SOLUTION: An optical waveguide 100 includes: a substrate 10; a modulation transmission line 1 that is formed by dividing along a propagation direction of light corresponding to each of modulation electrodes 1a to 1d; and a connection transmission line 2 that has connection electrodes to be connected to each of the modulation electrodes 1a to 1d, respectively. A characteristic impedance of the connection transmission line 2 is set so that a characteristic impedance composed of the modulation transmission line 1 and the connection transmission line 2 satisfies an impedance matching condition, and a length of the connection transmission line 2 is set so as to satisfy a velocity adjustment condition of a propagation velocity of light propagating an optical waveguide 12 and a propagation velocity of a high frequency signal propagating the connection transmission line 2.