Optimization Of Opto-electrical Conversion Performance And Its Implementation In High-speed And High-precision Photonic Analog-to-digital Converter

Analog-to-digital converter(ADC)is a key part of digital signal processing.Photonic analog-to-digital converters(PADC)have attracted great research attention content due to their large sampling bandwidth and high acquisition accuracy.In this thesis,we studied the optimization of the back-end opto-electrical conversion performance of PADC system based on optical sampling and electrical quantization.The main contents are as follows:Firstly,fundamental issues on several key devices and key technologies in PADC system were studied.The basic principles of optical sampling clock,electrical-optical modulator,photodetector and electric ADC and their time-domain model expressions are given,which provide theoretical basis for further research on the PADC system.Secondly,theoretical research on the nonlinear saturation effect of photodetector(PD)for opto-electrical conversion in PADC was carried out.The response model of PD was established and the simulation was performed with MATLAB.Then,for the single-channel and sub-sampling PADC system based on the passively mode-locked fiber laser and actively mode-locked fiber laser,the saturation effect of PD was investigated and experimentally improved by time-stretching method.The opto-electrical conversion responsivity and effective number of bits in PADC systems were also improved.Thirdly,according to shortages in a high-speed and high-precision photonic analog-to-digital conversion prototype system built by our group,we optimized the performance of the three core modules: sampling and multi-channel demultiplexing module,multi-channel opto-electrical conversion module and multi-channel quantization and reconstruction module.Measurement was carried out.