Based On Time Division Multiplexing Of Electro-optical Hybrid Modulus Conversion Structure Basic Research

With the rapid development of information technology, peopel make a realization of information query, voice-video communication, High speed signal recognition etc. by the network. These functionalities make future requirments for the transmission speed of the network information become higher and higher. High speed and high precision Analog-to-Digital Converter (ADC) is the most important part in the digital processing. At present, the electronic ADC can not be greatly enhanced in both Effective Number of Bits (ENOB) and sampling rate because of the influence of semiconductor fabrication process and material itself. The optical sampling and electronics quantitative method is mainly used by optical electronic ADC to achieve the conversion of analog signal to digital. It breaks through the bottleneck problem of the electronics by using optical properties, which has been paid attention by researchers around the word.The OE-ADC based on the Optical Time-Division Multiplexing (OTDM) multiplexes the optical signal through the signal modulation and the optical signal delay. Then the signal is samplinged and quantified by several electronic ADCs in parallel. At last, the sample value is arranged and restructured. The sampling rate of the system has been raised several times because the optical signal is divided into many channels. The quantitative accuracy of the system is determined by the electronic ADC, that means high quantization precision electronic ADC can be used to improve the system’s ENOB.The system noise mathematical model of analog optical links is constructed according to the effect the possible noise of every part of the system had on the final output signal ENOB in this thesis.With the experimental platform of500M sampling in4channels parallel, the experimental results can be acquired in the situation of the indirect and direct modulation system, in which the frequency of the RF is40M,50M,100M,250M, respectively. The final output signal’s ENOB of the system can be computed by the IEEE digital wave treatment formula. In the end,the experimental results and theoretical results were compared. Additionally,the impact of the signals with different frequency on the system’s ENOB and signal noise distortion is analyzed. The CNR calculation of Analogue Optical Links, implement method of optical fiber delay, offset point control of the modulator and the consistency of four channels are analysed in detail in this thesis. Especially a lot of investigation is made based on Bessel series expansion, which is significant to the analogue optical transmission system.