High Speed Optical Sampling Technique And Applications

The high-speed optical sampling technique is a key technique in modern information processing, ultrahigh-speed signal measurement and quality monitoring in the optical network. The principle and performance of optical sampling are presented in the thesis. The optical sampling with frequency-shift, asynchronous optical sampling, and photonic analog to digital conversion based on time-interleave were investigated, included the theoretical analysis and experimental demonstration. The actively and passive mode-locked fiber ring laser and two types of photonic switching, SLALOM (semiconductor laser amplifier loop mirror) and UNI (ultrafast nonlinear interferometer) were developed. This thesis presented the principle and the requirements for the optical of frequency-shift sampling module under common conditions. The waveform of 10GHz optical signal was observed on the oscilloscope with 100MHz bandwidth. The theoretical model of "lowpass filter" as the designing guideline for the selection of optical sampling width was proposed. The paper initiated electroabsorption modulator replacing the conventional model of sampling optical source and high-speed photonic switching. The novel approach greatly simplified the sampling system and improved the stability and reliability. It has been validated in experiment.In the fourth chapter of the thesis the principle of evaluating the bit rate error by synchronous and asynchronous histogram were shown. The asynchronous histogram of 10GHz microwave signal was achieved and the result was observed in experiment of 10GHz asynchronous optical sampling. The software synchronization method, which can be used to recovery the eye diagram of asynchronous sampling data, was analyzed. The error analysis model of sampling system was set up for the first time, by combining the saddlepoint approximation analysis and numerical arithmetic, which greatly increased the potential of further application and improved the reliability of the error approximation of the optical sampling histogram.The photonic analog to digital conversion based on time-intereleave wasstudied. The main error sources were analyzed and the requirements for the sampling pulse quality were simulated. The experiments of microwave signals sampled at different points by tuning the phase and optical delay line are demonstrated. The conversion precision is nearly 5 bits and 6 bits at 2.5GHz and 10GHz, respectively.