| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical modulator with which deterioration of electric reflection characteristics in a low frequency region is suppressed even when frequency characteristics of optical response are flattened by applying an electric filter circuit. SOLUTION: The optical modulator is equipped with: a substrate 10 with an optical waveguide 11 and an electric waveguide 12 formed thereon; a driving circuit 20 to generate a modulating electric signal S; a relay substrate 30 to impart the modulating electric signal S to the electric waveguide 12 via the electric filter circuit composed of a capacitor C1 and a resistor R1; and a terminal resistor R<SB>T</SB>to terminate the modulating electric signal propagated through the electric waveguide 12. The optical modulator is also constructed in such a way that the sum of impedance of the electric filter circuit and resistance of the terminal resistor R<SB>T</SB>is nearly equal to impedance of the driving circuit 20, and further resistance of the terminal resistor R<SB>T</SB>and characteristic impedance Z of the electric waveguide 12 are nearly equal to each other. COPYRIGHT: (C)2007,JPO&INPIT |
