Research On High Rate Optical Sampling Based On Optoelectronic Oscillator

High speed and high precision analog-to-digital converter(ADC)is one of the key technologies to be solved in the field of high-speed digital signal processing.By using the optical sampling technique,the photon ADC can break through the restriction of the electronic transit time uncertainty and aperture jitter of the traditional electric ADC.Meanwhile,it can improve the sampling rate of the ADC while maintaining the high accuracy.However,to achieve optical sampling with high efficiency and high performance,high repetition rate sampling pulse source technology and optical serialto-parallel conversion with large conversion ratio are of great importance.Through the research and analysis of the narrow pulse source,a scheme of optical sampling pulse source based on dual loop optoelectronic oscillator is proposed in this paper.Different from traditional sampling pulse source technology,sampling pulse source based on OEO can generate microwave signals with high repetition rate and low phase noise directly.In order to obtain wide spectrum sampling pulse source,OEO and direct tuning laser and phase modulation laser are combined,then optical sampling pulse of 10 GHz is obtained directly.The experimental system has no external microwave source,and the transient stability of the optical pulse generated depends on the stability of the microwave signal generated by the OEO system.Finally,10 GHz repetition rate,195 fs time jitter,and 64.33 dB side mode suppression ratio is obtained.The linewidth is 22 ps,and the spectral width is 0.8nm.In the research of high-speed optical string parallel conversion technology,the traditional optical string parallel conversion requires higher linewidth and spectral width of optical pulse,and this paper adopts sampling method based on Fourier transform in time domain.By sampling with linear chirp pulse sampling signal,amplitude information of the signals at different time points were modulated to different wavelength pulse sampling,by filtering out the pulse sampling of different wavelengths of light can be realized,sampling and serial parallel conversion at the same time,to achieve real-time high speed sampling.Finally,by using time domain Fourier transform sampling technique based on double loop OEO,we realize the high speed optical sampling of DC,10 GHz sinusoidal microwave signals and 2.5GHz square wave signals.The sampling rate is 40GSa/s,and the ratio of series to parallel conversion is 4.