Integrated optic modulator with reduced capacitance electrode

Abstract

An optic modulator implemented on a substrate that is conductive to light and which includes a pair of light waveguides formed on the substrate is described. The waveguides extend substantially coextensively with one another and are separated from one another by a transverse distance that gradually varies along the courses of the waveguides. The waveguides are arranged to pass between an outer electrode assembly and a center electrode assembly. The outer electrode assembly substantially surrounds the center electrode assembly in such a manner as to create an electric field between the center electrode assembly and the outer electrode assembly when a voltage is applied across the outer and center electrode assemblies. In order to minimize the effective capacitance resulting from the interaction of the outer electrode assembly and the center electrode assembly, the center electrode assembly is implemented using a plurality of individual electrode segments arranged to maximize the electric field strength generated in the area though which the waveguides pass while minimizing the overall effective capacitance. By using such a center electrode configuration, the capacitance is decreased and thus the overall bandwidth of the modulator of the present invention is increased as compared to modulators using a single solid center electrode.