Design Of Front-End Amplifier Of 10Gb/s Optical Receiver With Analog Equalizer

With the rapid development and wide application of optical fiber communication system, information exchange becomes more and more fast. At present, people’s demand for short distance optical communication system becomes more and more urgent. This results in the rapid growth of the demand of high quality optoelectronic components and modules.As the plastic optical fiber(POF) shows good performance in the short distance optical communication system, Local optical network, optical fiber to the home and Vehicular optical networks have been further developed. New high-speed optical receivers are required because of the popularity of short distance optical communication system. Optical receiver designed in standard CMOS process has lower cost, and the integration with the digital circuits are easy to implement. Now, With the research and application of CMOS optical detector, monolithic integrated optical receiver has become a new proposition of IC design.The front-end amplifier of the optical receiver is the key part of monolithic integrated optical receiver, and it includes photodetector(PD), transimpedance amplifier(TIA), equalizer and the main amplifier. The front-end amplifier determines the performance of the whole optical receiver.Optical detector is used to convert optical signal into current signal. In this paper, a kind of photodetector with double photodiode structure is implemented in standard CMOS technology. The transimpedance amplifier is used to convert current signal into voltage signal, and enlarge the signal at the same time. The modified regulated cascode(RGC) structure is chosen because it has low input impedance and broad bandwidth. Continuous time linear equalization(CTLE) structure is used as equalizer because of its simple structure and small chip area. The limiting amplifier(LA) structure is applied because of its simple structure and low power consumption.The circuit structure and layout design is based on TSMC 0.18μm CMOS process. In this paper, Virtuso and Spectre software are used under the Cadence platform for simulation. The simulation results indicate that the trans-impedance gain of the front-end amplifier is 94.7dBΩ and the-3dB bandwidth is 7.7GHz. The whole dissipation is 151mW when the supply power is 1.8V.