Research On Tunable Microwave Photonic Filter Based On Photonic Crystal Fiber

Microwave photonics combines microwave technology and photonics,and merge two academic advantages,has broad application prospects.Overcomes the bottleneck problem of radio frequency signal processing in the electric field compared with the traditional electronic filter.Microwave photonic filter has the advantages of high bandwidth,low loss,small volume and anti-electromagnetic interference,which widely used in the field of communications.This thesis studies tunable MPF based on photonic crystal fiber by means of theoretical,the main contents and innovation points are as follows:(1)The basic principle and application of microwave photonic filter,the classification of microwave photonic filter according to different characteristics,summarizes the research status of tunable and reconfigurable microwave photonic filter.The research status of microwave photon filter in recent years is summarized.(2)The basic principle of microwave photonic filter is described,theoretical analysis of basic principle of MPF which based on phase modulation are given and the design methods of tunable MPF are discussed,application research of photonic crystal fiber in MPF.(3)A microwave photonic filter based on HB-PCF and grating pair is proposed.When multi-wavelength fiber laser as the light source,the HB-PCF will own different birefringence by varying the temperature of HB-PCF which filled with temperature-sensitive liquid.With the continuous change of HB-PCF birefringence,the laser output has different wavelengths which make the microwave photonic filter owns different free spectral range.By introducing single-mode optical fiber and grating cascade,which improve its frequency selectivity.(4)A ultra wideband tunable microwave photonic filter based on HB-PCF and fiber ring is proposed.When multi-wavelength fiber laser as the light source,the HB-PCF will own different birefringence by varying the temperature of HB-PCF which filled with temperature-sensitive liquid.With the continuous change of HB-PCF birefringence,the laser output has different wavelengths which make the microwave photonic filter owns different free spectral range.By introducing fiber ring cascade,which improve its frequency selectivity.(5)Tunable microwave photonic filter based on HB-PCF delay element is presented.A HB-PCF filled with temperature-sensitive liquid is served as delay component for the delay unit.The HB-PCF will own different birefringence by varying the temperature of HB-PCF which filled with temperature-sensitive liquid,the delay difference between the signals along the fast axis and slow axis of the HB-PCF is changed,Thus the filter is obtained with different free spectral range.