Photonic-Assisted Microwave Photonics Signal Generation And Processing

Microwave photonics is a interdisciplinary course to achieve the microwave signal generation,control,processing and transmission based on optoelectronic devices and photonics theory,which does not only have the traditional microwave characteristics of flexibility,flexible,ubiquity and high spectral resolution,but also integrates the photonic technology with low loss,high bandwidth,anti-electromagnetic interference,tunable and reconfigurable advantages.Microwave photonics is one of the technical ways to solve the problems including the insufficient spectrum resources which the current data transmission system is facing,transmission loss and high energy consumption.It has wide applications on broadband wireless access network,sensor network,radar,satellite communication and electronic warfare system.Based on the electro-optic and non-linear theory of optoelectronic devices,this thesis discuss a series of investigations on how to realize the production of all-optical microwave signals and microwave signal processing technology.The main contents are as follows:1.Based on the principle of nonlinear polarization rotation(NPR)in high nonlinear fiber(HNLF),the generation of all-optical frequency shift keying RF signal is realized.A pump optical signal using the amplitude shift keying generates a polarization rotation effect in the HNLF.The other continuous wave probe beam is polarization modulated.After the tunable optical filter and the polarizer,the rotated probe beam is converted into an intensity modulated signal.By proberly setting the polarization controller and the polarizer,a frequency-shift keying RF signal is finally produced.The experimental results agree well with the theoretical analysis.The proposed solution is helpful for breaking through the bottleneck of electronics bandwidth and providing a technical solution for future ultra-wideband,formatted,all-optical signal processing.2.Based on properly setting a dual parallel Mach-Zehnder modulator(DPMZM)and an optical notch filter(ONF),a scheme of microwave photonic notch filter with high-linearity and large tuning range is proposed.A single sideband modulation of the optical carrier signal is realized by tuning the amplitude and phase of the DPMZM,which suppresses the generation of the third-order inter-modulation signal,reduces the nonlinear effect and improves the dynamic range of the filter.In addition,the continuously adjustable and high linear filtering of the microwave photonic notch filter is realized in the frequency range of 16 GHz to 26 GHz by adjusting the center wavelength of the tunable laser.