A wideband electro-optic modulator based on long range surface plasmon resonances

A wideband electro-optic (EO) modulator based on long range surface plasmon resonances is proposed and numerically demonstrated. The modulator model consists of a prism-dielectric-metal-EO polymer-metal structure, using attenuated total internal reflection to excite long range surface plasmon resonances and a conductor-backed coplanar waveguide to distribute radiofrequency (RF) electrical signals. The parameters of the structure are optimized and the results show that the different frequency signals with voltages of 1.36 V at 6 GHz, 2.03 V at 20 GHz and 2.71 V at 60 GHz are enough to achieve a modulation index of 15.2%. The maximal modulation index can reach 76% ranging from DC to 60 GHz by increasing the input RF voltage, and the insertion loss can be decreased to 4.2 dB by adjusting the operating bias. High modulation efficiency, wide operating bandwidth and low insertion loss are realized simultaneously in this design.