High-Performance TO Switches on Compact Cu-Dielectric-Si Hybrid Plasmonic WRRs

We present plasmonic thermo-optic (TO) switches made of compact Cu-dielectric-Si hybrid plasmonic waveguide ring resonators (WRRs), which offer high tuning efficiency and fast switching speed by placing a metal heater closely above the Cu cap and choosing a material with high TO coefficient as the sandwiched dielectric. Prototype devices with 2.5-μm radius and Si3N4 as the dielectric are fabricated on the silicon-on-insulator platform using standard complementary metal-oxide-semiconductor technology and are measured at 1.55-μm telecom wavelengths. They exhibit a Q-value of ~166, a tuning efficiency of ~1.1 nm/mW, a response time of ~6.5 μs, and an output modulation of ~5 dB under a 5 V/10-kHZ driving voltage. Methods for further performance improvement are addressed.