Design Of Laser Drive Circuit Based On On-chip Transformer Peaking

Nowadays,optical fiber communication has become the most popular information exchange technology.With the rapid development of society,the demand for increasing the information transmission rate is also increasing.Under the research of scientists,the transmission rate of optical fiber communication technology has been rapidly improved,and it is still developing.The main factor limiting the transmission rate of optical fiber communication is not the fiber channel or the laser diode,but the optical transceiver circuit.For example,the function of the laser drive module is to drive a laser diode,which converts a high-speed voltage signal into an optical power signal.The design challenge is to overcome capacitive loading of laser diodes,transistors,and I/O interfaces.Therefore,how to increase the transmission rate of the laser driver circuit by bandwidth extension technology has become the focus of research.For the problem of bandwidth limitation,this paper has analyzed the technical difficulties of the laser driver circuit based on the CMOS process,and has improved the traditional laser driver circuit.Firstly,the circuit was designed and the transformer peaking technique has been proposed.Then the on-chip transformer has been designed and modeled.Finally,it has been verified by manufacturing test.The main work is as follows:1.A laser drive circuit based on on-chip transformer peaking has been designed.Firstly,the principle and non-ideal factors of laser diodes driving have been analyzed.Secondly,the principle and performance of laser driver circuit have been described,and the transformer peaking technique has been proposed to address the bandwidth limitations of the output current.Thirdly,the input buffer stage,main amplifier stage and output stage of the circuit have been analyzed.Finally,the results have been verified by circuit simulation.2.For the application of the laser driver circuit,a circular on-chip transformer with plane crossover has been designed.Firstly,the performance and design specifications of the on-chip transformer have been described,and the loss mechanism has been analyzed.Then the on-chip transformer has been analyzed and modeled,and a novel equivalent circuit model has been proposed for the transformer design and optimization.Finally,the component parameters of the equivalent circuit model have been extracted,and the model has been verified by electromagnetic simulation.3.The laser driver circuit based on the on-chip transformer peaking has been fabricated,and the measurement results show that the output modulation current is 12 mA,the rise/fall time is 181/197 ps,the circuit core power consumption is 37 mW and the area is 0.35 mm,when the working voltage is 1.8V,the input is a differential pseudo-random signal with a single-ended peak-to-peak value of 400 mV,the rate is 2Gbit/s.Compared with the laser driver circuit using other bandwidth extension technologies,the laser driver circuit based on on-chip transformer peaking designed in this paper has higher transmission efficiency and more power saving.