100khz-10 Ghz, For The Optical Receiver Front-end Distributed Amplifier

Preamplifier is one of the most important components in photoreceiver front-end. It directly affects the performance of light receivers such as speed, noise and sensitivity. Traditional pre-amplifier's cut-off frequency is confined to parasitic parameters of active devices. So it just used as simple negative feedback, although it could extend the bandwidth to some extent, but still can not meet the demand of high-speed optical transmission system. High-speed and high-capacity optical transmission systems need to seek new structure of amplifier to meet the growing bandwidth requirements. Distributed amplifier which has characteristics of ultra-wideband, low noise, high gain etc is a good option of photoreceiver pre-amplifier.MIC distributed amplifiers with good performance and low-cost has been designed in this paper. Its performance is 10 GHz bandwidth, 10 dB gain and less than -10 dB reflection. Firstly, we analyze the basic principle of the distributed amplifier, describe integrated design method of distributed amplifier and introduce two kinds of improved distributed amplifier including the matrix distributed amplifier and the variable impedance distributed amplifier. Then a multi-octave MIC distributed amplifier used in optical receiver front-end has been designed through ADS design simulation. Also analyze the problems produced in the design process. The performance of the distributed amplifier high frequency gain is improved by the parallel capacitor in FET drain and the series capacitors in FET gate.Finally the amplifier's gain and noise have been measured desperately at room temperature and low temperature to research amplifier performance in low temperature. The amplifier is mainly used for amplifying the weak pulse signals that thansformed from optical signals in optical receiver front-end. It can also be used as low noise amplifier in broadband high-temperature superconducting receiver front-end.