A 40 Gbit/s fully integrated optical receiver analog front-end in 90 nm CMOS

A fully integrated 40 Gbit/s optical receiver analog front-end (AFE) including a transimpedance amplifier (TIA) and a limiting amplifier (LA) for short distance communication is described in this paper. The proposed TIA employs a modified regulated cascode (RGC) configuration as input stage, and adopts a third order interleaving active feedback gain stage. The LA utilizes nested active feedback, negative capacitance, and inductor peaking technology to achieve high voltage gain and wide bandwidth. The tiny photo current received by the receiver AFE is amplified to a single-ended voltage swing of 200 mV(p-p). Simulation results show that the receiver AFE provides conversion gain of up to 83 dBΩ and bandwidth of 34.7 GHz, and the equivalent input noise current integrated from 1 MHz to 30 GHz is about 6.6 μA(rms).