Research On Optical Delay Analog To Digital Conversion Technology

Analog to digital converter(ADC) is a kind of device that converts analog signals to digital signals, which is essential component for the transmission and processing from analog signals to digital signals. With the continuous improvement of the social digital process in recent years, the electronic ADC is unable to meet the increasing sampling rate and bandwidth demand due to the electronic bottleneck. However, photonic ADC can overcome this problem to achieve ultra high sampling rate and ultra wide bandwidth. So it is considered to be the best option to replace the electronic ADC.This thesis first briefly reviews the development process of photonic ADC and combined with recent research to compare the advantages and disadvantages of each photonic ADC. Then we emphatically introduce and analyze a photonic ADC based optical delay. Through theoretical analysis and experimental verification, the system principle and the parameters affecting the system performance of ADC are discussed.In the part of theoretical analysis, we first expound the function of each components and the optical delay ADC’s working principle, which is using optical splitter and optical delay line to achieve time division multiplexing. So it is able to have high sample rate by using parallel sampling. Then, according to IEEE Standard for ADC testing, we deduce some mathematical models which is that the ADC’s effective number of bit(ENOB) is effect by some factors such as delay time error, loss difference of splitter, detector noise and so on.In the part of experiment, a four channel optical delay ADC which has 500MS/s sample rate and 7bits has been designed and implemented. Based on this ADC, the different channel and frequency comparative experiments have been done, and results have been analyzed. Then we designed the two channel optical ADC system which has time delay error and detector difference to compare with standard two channel ADC system. The results of experiment verify the theoretical analysis.At last, we evaluated the development trend of optical delay ADC and analyzed the system scheme and technology difficulties to achieve high sampling rate optical delay ADC.