Electro-absorption modulation in horizontal metal-insulator-silicon-insulator-metal nanoplasmonic slot waveguides

An ultracompact, broadband, and fully complementary metal-oxide-semiconductor (CMOS) compatible Si nanoplasmonic electro-absorption modulator is proposed based on the recently developed horizontal metal-insulator-silicon-insulator-metal nanoplasmonic slot waveguide. The modulation relies on a highly accumulated electron layer at the insulator/Si interface induced by an applied voltage. Proof-of-concept devices are fabricated using standard Si CMOS technology. A 3-dB modulation around 1550 nm is measured under similar to 6.5 V bias for a device with total length of only 4 mu m. The design suggests that larger modulation could be achieved by using high-kappa dielectrics as the insulator, thinning down the insulator thickness, and narrowing the Si core of the nanoplasmonic waveguide. (C) 2011 American Institute of Physics. [doi:10.1063/1.3653240]