Research On Photonic Frequency-multiplying Millimeter-wave Generation And Phase-coded Technology Based On Dual-parallel Mach-zehnder Modulator

With the rapid development of the information society,the demand for high-speed,massive and long-distance data transmission and broadband access is increasing.Radio over Fiber(ROF)has become a hot topic of current research.Photonic generation of millimeter-wave signals can highlight the low cost and high transmission performance of ROF systems,Using photonic techniques to generate microwave pulse signals with large time-bandwidth products can overcome the limitation of "electronic bottlenecks" and meet the demand for detection range and resolution of modern radar systems.This thesis will focus on two aspects that the use of optical methods to generate high-frequency millimeter-wave signals and the use of optical methods to process microwave signals.Firstly,the research background of this thesis is summarized,and the domestic and international research status of the generation and processing of microwave millimeter wave signals is introduced.Then the theoretical analysis and formula derivation of several optical-external modulators are carried out and the simulation of DPMZM is realized in Optisystem by Matlab Component.Secondly,the key techniques of optical millimeter-wave signals generation are introduced,focusing on the analysis of the external modulated technique which is considered to be the best solution for photonic generation of millimeter-wave signals.In the aspect of using optical method to generate millimeter wave signals,this thesis proposes two multiple frequency millimeter-wave generation methods based on cascaded and parallel DPMZM,and realizes the optical generation of millimeter wave signal via frequency 16-tupling without any electric or optical filter,discussed the effects of modulation depth and phase shift of the phase shifter on the performance of the millimeter-wave signal.Two methods for optical generation of millimeter-wave signals via frequency 16-tupling and 24-tupling based on a single DPMZM combined with nonlinear effects are proposed.In the first scheme,the four-wave mixing effect of SOA is used to generate higher harmonics,and the unrelated sidebands are filtered by the filter,and finally the generation of the twenty-four times frequency millimeter-wavesignal is realized.In the second scheme,the stimulated Brillouin scattering effect is used to suppression the fourth-order sidebands without using a filter,and finally a pure eighth-order sideband is obtained,the generation of the sixteen times frequency millimeter-wave signal is realized.Finally,in the aspect of processing microwave signals by optical method,this thesis proposes a method based on DPMZM and a polarization-maintaining Bragg grating to realize the simultaneous generation of two arbitrary phase-coded microwave signals.Separating two channels ±2 order sidebands of orthogonal polarization by the interaction of the polarization-maintaining fiber bragg grating and polarization beam splitter.One pair of sidebands is modulated by a phase modulator and then coupled with another pair,and finally send them to two photodetectors to obtain high frequency phase-coded microwave signal.The experimental results show that by adjusting the frequency of the driving signal,a series of quadruplicated frequency phase-coded microwave signals of 5 GHz-100 GHz can be obtained.The restored phase information and pulse compression ratio are consistent with the theoretical values,which proves the validity of the proposed method for generating multi-channel phase-coded signals.