Front-end circuit of high-speed optical receiver and its low-noise processing method

Abstract

The invention provides a front-end circuit of a high-speed optical receiver and a low-noise processing method thereof. The front-end circuit comprises a first resistor connected between a power supplyvoltage and a cathode of a photodiode; a level shifter connected to a photodiode cathode; a first transimpedance amplifier connected to the level shifter; a second transimpedance amplifier connectedto the photodiode anode; an automatic gain controller connected to the first and second transimpedance amplifiers and configured to compare the magnitude of the output signal of the first and second transimpedance amplifiers with a reference value, and adjust the first resistor, the first and second transimpedance amplifiers according to the comparison result, thereby keeping the magnitude of theoutput signal of the first and second transimpedance amplifiers constant. The invention adopts the mode of differential input and differential output to increase the output swing by two times, improvethe effective gain of the circuit, effectively improve the output signal-to-noise ratio of the transimpedance amplifier without increasing the output noise of the transimpedance amplifier, and further improve the sensitivity of the transimpedance amplifier.

Description

technical field [0001] The invention relates to the field of high-speed optical communication transceiver chips, in particular to a front-end circuit of a high-speed optical receiver and a low-noise processing method thereof. Background technique [0002] At present, the bandwidth demand of high-speed interconnection networks such as data centers is getting higher and higher. Due to its disadvantages in cost and performance, the traditional electrical interconnection is increasingly replaced by optical fiber communication with low price, large capacity, small crosstalk, and strong anti-electromagnetic interference. obvious. However, as the core of optical communication interconnection, the current high-speed optical communication transceiver chips (drivers, cross-group amplifiers, limiting amplifiers, and clock data recovery circuits, etc. are designed and manufactured using traditional SiGe / GaAs and other processes, and their bandwidth and noise performance is superior. Bu...

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Problems solved by technology

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a front-end circuit of a high-speed optical receiver and a low-noise processing method thereof, which are used to solve the problem of poor noise performance of a high-speed optical receiver of a CMOS process in the prior art. question

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