On-chip optoelectronic logic gates operating in the telecom band

Optoelectronic logic gates (OELGs) are promising building blocks for next-generation logic circuits and potential applications in light detection and ranging, machine vision and real-time video analysis. On-chip OELGs operating at telecom wavelengths are highly desirable for integration with the growing possibilities offered by silicon-based optoelectronics. However, at present operations are limited to linear logic functions in the ultraviolet or visible range and high-performance OELGs for multiple logic functions are lacking. Here we integrate up to three silicon waveguides with black phosphorus for optoelectronic logic operations at 1.55 μm. We demonstrate linear (AND, OR, NOT, NAND, NOR) and nonlinear (XOR and XNOR) OELGs by programming optical inputs into the waveguides and reading out electronic signals. The devices exhibit a responsivity as high as 0.35 A W−1and a 3 dB bandwidth of 230 MHz. The combination of a photovoltaic OR gate and a voltage-switchable AND gate enables two-layer composite logic computing in the form (A + B)C. We also demonstrate symbol recognition, edge extraction, image fusion and encryption/decryption performed by these OELGs. This work paves the way for the development of new optoelectronic logic computing circuits.