Optical modulation element

Abstract

[Problem] To provide a light modulation element whereby speed matching of light and microwaves and reduction of driving voltage can both be achieved. [Solution] A light modulation element (1) comprises a substrate (10), first and second waveguide parts (2A, 2B) comprising an optical material film having a ridge part which are disposed on the substrate (10) and provided parallel to each other, a buffer layer disposed on the first and second waveguide parts (2A, 2B), and first and second signal electrodes (5A, 5B) provided along the first and second waveguide parts (2A, 2B). The first and second signal electrodes (5A, 5B) have solid-line parts (51) provided continuously in a travel direction and provided respectively on the outside of the first and second waveguide parts (2A, 2B) in plan view, dashed-line parts (52) provided intermittently in the travel direction and provided respectively in positions overlapping the first and second waveguide parts (2A, 2B) in plan view, and connecting parts (53) for connecting the solid-line parts (51) and the dashed-line parts (52). The width (W2) of the dashed-line parts (52) is greater than the width (Wr) of the ridge parts.

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