Study Of Pre-emphasis Circuits For Silicon-based Optoelectronic Devices

The pre-emphasis circuit,as a new-type electrical signal waveform generation circuit,operates by pre-loading a short pulse high potential on the applied normal bias voltage.The purpose is to improve the carrier injection velocity in the intrinsic area of the PIN,increase the internal carrier concentration as well as reduce the composite life of carrier so as to enhance the response speed of the PIN based carrier injection optoelectronic devices.In this paper,on account of the analysis of the working principle of the PIN based carrier injection optoelectronic devices,three different new pre-emphasis circuit design schemes are proposed by taking the pre-emphasis circuit as the research object,combining with the research status of scientific research institutions at home and abroad as well as utilizing the basic theory of integrated circuit design.Therefore,it can achieve the design goals of reducing power consumption,simple structure,the output flexibility.The research of the paper mainly involves the following three parts:1.Pre-emphasis circuit design based on current selector: through the in-depth study of the working principle of the current mode logic circuit together with the waveform characteristics of the pre-emphasis signal,the two-tap parallel current mode logic circuit is used as the pre-emphasis signal generation circuit.At the same time,the application of low voltage differential signal circuit can achieve different current switching options so that it can reduce the power consumption of the circuit.2.Pre-emphasis circuit design based on regenerative comparator: under the positive feedback charging and discharging working principle of the regenerative comparator,aiming at the the requirement of waveform of the pre-emphasis electrical signal,the appropriate improvement of the discharge speed of the regenerative comparator,can meet the high-speed and stable requirements that the pre-emphasis circuit demands.3.Pre-emphasis circuit design based on cascode pseudo-differential structure: it is proposed to construct the pre-emphasis circuit by using the cascode pseudo-differential structure under the low power supply voltage.According to the relationship between the input and output of this structure,folded-cascode op amp negative feedback bias circuit based on resistor divider is designed by using the "virtual short" characteristic of op amp.Thus,it can achieve different bias inputs for the cascode pseudo-differential structure,and then complete the flexibility and adjustability of the pre-emphasis circuit output.The three different pre-emphasis circuit structures proposed above are designed with the 0.18 ?m TSMC CMOS technique and verified using the tool of Spectre.The results show that in comparison with the performance of traditional pre-emphasis circuit,it possesses the characteristics of simple structure,stability,high efficiency as well as the adjustability of voltage.Moreover,it has also improved the performance of the PIN based carrier injection optoelectronic devices.