Study On Phase Modulator Based Optical Analog To Digital Conversion

Analog-to-digital converter(ADC) is the device that converts analog signal into digital signal. As the bandwidth and accuracy requirement of signal processing in communication and research rises, ADCs with higher sampling rate and effective number-of-bits(ENOB) are expected. Also the progressive digital signal processing and storage technology supports ADC’s development. The electronic ADCs’ bandwidth and accuracy have raise a lot among decades of researching, but it will be hard to improve dramatically according to the limitation of electronic bottleneck on timing jitter.According to the benefits on large bandwidth and high stable, photonics has been induced into ADC research to improve ADC’s performance. Conventional optical intensity modulator based analog to digital conversion scheme have some restraining factors such as bias drift, arms asymmetric structure. It also has the advantages like high linearity. These conditions are provided to achieve the phase modulator based high-precision optical analog to digital conversionThis dissertation studies the phase modulator based high-precision optical analog-digital conversion technology, explains how it works, analyzes the main factors that affect system performance, and feasibility and validity of the system are verified by experiment.First, the dissertation describes the structure of the phase modulator based optical analog to digital conversion system, and the working principle of this program are analyzed, the changes of phase and polarization state are illustrated, and signal recovery method for the system is given.Secondly, this dissertation introduces the main measure of analog to digital conversion system performance, analyses the main factors that affect the optical analog-digital conversion system performance, including optical sampling clock amplitude jitter, optical sampling clock time jitter, change of polarization state, and multi-wavelength correlations.Finally, this dissertation gives the results of an optical phase modulator based analog to digital conversion experiment. Introduces the single-wavelength experimental system structure and the instrument used, the structure of OTDM module is introduced too. The experiment verifies the amplitude jitter suppression of dual-port recovery mothed, analyses the influence of handmade OTDM module delay error, and describes the adjustment and correction process of the sampling clock polarization state. This dissertation also describes the correction process and experimental results, gets the conversion results of 6.38 bits in the sampling rate of 583MS/s. Finally, the test result of 128GS/s optical sampling clock repetition multiplier module based on OTDM and WDM is introduced.