Research On Optical Quantization Based On Mach-zehner Modulator And Optical Coding Based On Silicon Waveguide

In the information age,digital signal processing has become an indispensable important component of varied needs. However, most of the natural signals exist in the form of analog,so, there is urgent need of a device to covert the analog signal to digital one, ADC is indeed what we want. As the continuous requirement of higher speed rate, higher waveband, and higher stability, Traditional electric ADC's inherent drawbacks have limited its development. While photonic technology can come to meet the demands of high bandwidth, high sampling rate, and high resolution.Optical quantization based on unbalanced Mach-Zehnder modulator is an effective mean to realize all optical quantization. This thesis elucidates the optical quantization theory of Mach-Zehnder modulator and give the error analysis method.Then put forward a new quantization scheme of cascaded unbalanced Mach-Zehnder modulators, derive the theory of this module, measure and analyze that only use three wavelengths, a number of bit of 4 is achieved, when the number of available wavelengths increase to 129, the number of bit is up to 12bit. This thesis also analysis several possible factors that might decrease the final quantization resolution and give their effect trend.This thesis design a new structure of optical coding, give scheme of binary encoding and gray encoding, and compare their difference, advantages and disadvantages, and find repeating substructure in the module. Design new Y-branch and tri-branch power splitter, and analyze the coding performance of this method. this thesis also analysis the variant design of Y-branch structure, like the difference between the two branches length and refractive index, and discuss its influence on coding performance, in order to seek the way to further reduce the bit error rate and improve the bandwidth utilization.