Design And Implementation Of Limiting Amplifier In 25Gbps Optical Receiver

With the advent of the information age,large amounts of data are continuously being generated through various channels.Big data and cloud computing technologies were proposed to address the need to process a growing volume of data.High-quality communication networks are required for cloud computing and big data technologies.Traditional radio wave communication is not well-suited for this task.The optical communication system,with its high speed,stability,and low loss,has become the foundation of cloud computing and big data technologies.In optical fiber communication systems,the optical receiver is crucial and often limits the rate of optical communication.As a key module in an optical receiver,the limiter amplifier is mainly used to amplify and shape the signal,and its performance has an important impact on the performance of the whole optical receiver.In order to improve the rate of the optical receiver,a high rate limiter amplifier must be implemented.This study has developed a high-speed limiting amplifier suitable for a data transmission rate of 25 Gbps.The limiting amplifier is composed of the main limiting amplifier path,a DC offset cancellation circuit,and a signal loss detection circuit.The limiting amplifier adopts a fully differential structure,which can suppress the common-mode noise of the circuit to a limited extent.Inductor peaking technology and negative capacitance technology are used to improve the bandwidth of the limiting amplifier.Equalization technology is used in the input stage of the limiting amplifier to improve signal integrity.A DC offset cancellation circuit is implemented to solve the problem of device mismatch.To improve the versatility of the circuit,a programmable signal loss detection circuit with adjustable threshold values is implemented in the limiting amplifier.The limiting amplifier is designed,simulated,and measured using0.18 um BICOMS technology,with the chip area being 467μm×520μm.Post-simulation results show that the intermediate frequency gain of the limiting amplifier is 42.7d B,the bandwidth is 19.1GHz,and the differential output swing is about 800 m V.The power consumption is only 50.4m W.Simulation of eye diagrams of the limiting amplifier under different PVT conditions shows small output jitter,good eye opening.The limiting amplifier is fabricated and tested in an actual working environment.Measurement results of the eye diagram show that the output jitter of the limiting amplifier is about 8ps,with good eye opening,normal eye height of about 600 m V,and good symmetry under the condition of an input optical signal rate of 25 Gbps.The limiting amplifier can meet the signal transmission requirements of a data rate of 25 Gbps.