Low-Noise Front-End Amplifier Design for 10Gbps Optical Receiver

A critical performance metric for optical receiver is sensitivity which is limited by noise. In optical receivers, achieving a low-noise front-end amplifier while maintaining bandwidth is a challenge. This challenge arises due to the trade-off between bandwidth and noise. This paper proposes a circuit design to break this trade-off using a two-stage cascaded circuit. Noise is solved by using a shunt-feedback transimpedance amplifier (TIA) with big feedback resistor and the bandwidth limited by TIA will be compensated by continuous-time linear equalizer (CTLE). The circuit simulation achieves a transimpedance gain of 82dB, a -3dB bandwidth of 7.6GHz, and an input reference noise of 0.27μA, meeting bandwidth and low-noise requirements in optical receiver.