On-chip high-speed optical detection based on an optical rectification scheme in silicon plasmonic platform.

We theoretically investigate the nonlinear optical rectification (OR) process induced in a silicon plasmonic slot waveguide (PSW) with an electro-optic polymer infiltrated into the slot. An electrical signal is generated between the two metal slabs when an intensity-modulated optical signal is injected into the PSW. Optimization of the geometrical parameters is performed to obtain the highest OR efficiency. Specifically, a voltage responsivity over 1V/W and a normalized OR efficiency of 2.25 × 10(-4)W(-1) are predicted in a compact PSW with active size of 50nm × 90nm × 22.4μm for a modulation speed of 400GHz. The OR efficiency is further increased when introducing the electrically induced OR contribution. The OR characterizes a relatively flat response for a wide range of optical wavelengths from 1.25μm to 1.7μm and supports a RF cut-off frequency up to 800 GHz. This efficient OR process paves a new way for realization of high-speed broadband optical detection and demodulation in silicon chips.