Research Of Photodetector And Analog Front-end Circuit Of Optical Receiver For Optical Communication

With the maturity of technologies such as intelligent AI,Internet of Things and5G information transmission volume and transmission rate grows dramatically.Due to the high loss and crosstalk,the traditional copper interconnect has become difficult to accommodate the ultra-high-speed data transmission.As an ideal alternative solution,optical interconnection,which chooses the photon as the information carrier,has many advantages,such as low loss,high bandwidth,small crosstalk and no impedance matching,et al.Therefore,it is a next development trend of future interconnection.As a key block building of the optical interconnection system,the optical receiver in standard silicon-based process has become a hotspot in the field of optoelectronics.Silicon compatible optical interconnects,which use the architecture similar to the integrated circuits,can significantly improve the integration,manufacturability,and extendibility by utilizing standard technology facilities,experiences,and techniques to design,fabricate,and package optoelectronic integrated circuits.The standard SiGe BiCMOS process has better optical properties,and provides the unique SiGe heterojunction bipolar transistor(HBT)with high transconductance and high bandwidth.Therefore,it is an ideal technology for the broadband optical receiver system.Many domestic and foreign scholars have begun some research on optical receivers based on the standard SiGe BiCMOS process,but the results are still far from the commercialization standards.To achieve the wide-band optical receiver analog front-end circuits for the optical interconnection based on the standard silicon-based technology,the research works carried out in this thesis are as following:1.Based on JAZZ SiGe BiCMOS technology,two novel photodetector is designed and simulatied.An HPT detector with a bandwidth of about 3 GHz and high responsiveness to light at 500 nm wavelength.Another lateral PIN photodetector has a bandwidth of about 7 GHz and is best responsive to incident light at a wavelength of700 nm and can be used for communication at 850 nm wavelength.2.Based on JAZZ SiGe BiCMOS technology,an overall circuit was designed and optimized,including transimpedance amplifier with bootstrap circuit to eliminate the equivalent input capacitance of the detector,limiting amplifier with Cherry-Hooper configuration,and f_T output buffer.Post simulation results indicated that the receiver circuit has a transimpedance gain of 85.1dB?and a bandwidth up to20.7GHz.3.Based on UMC 0.18?m CMOS technology,a modified low noise shunt feedback transimpedance amplifier(TIA)was designed and fabricated.The measured results demonstrated that the fabricated TIA with a photodetector capacitance of 300pF and 1.8V supply voltage has a transimpedance gain of 59.5 dB?and a-3dB bandwidth of 4 GHz,and the average input-referred noise current spectral density is less than 7 pA/?Hz.The eye pattern measurement shows that a data rate of 5Gb/s is successfully achieved.The chip consumes 35mW DC power and occupies an area of0.77×0.35mm~2.