Research On Incoherent Microwave Photonic Filter And Its Application In Sensing

Since mankind entered the information age,traditional electrical-technology is becoming more and more difficult to meet the communication needs of society.With the rapid development of photonic-technology,the inter discipline called microwave photonic technology,which combines the advantages of photonic technology and electronic technology emerged.Microwave photonic technology allows traditional electrical signals to be generated,processed,and transmitted in optical domain,and it has a series of advantages such as the immunity to electromagnetic interference,light weight,low loss and so on.Therefore,it is widely used in popular areas such as contemporary optical communication,biosensing,and autonomous driving.In this thesis,microwave photonic filters(MPF)based on the first-order Sagnac,second-order Lyot-Sagnac and second-order Solc-Sagnac structures have been proposed,theoretically analyzed by using Matlab for simulation and demonstrated in experiments.In addition,MPF based on fiber ring structure and EDFA is also explored in sensing system,where relatively satisfactory results have been achieved.These works have some reference value for future MPF system design.Firstly,the principle of typical microwave photonic technology is described in detail.According to the different components of the system,the research process is discussed separately.Then,several main research directions and application fields of microwave photonic technology are presented.Then,MPF are classified according to different standards,the principle and structure of several different types are pushed out respectively.The characteristics of MPF filters are summarized,and several popular research directions are listed in the light of actual requirements.Next,we explored the aperiodic incoherent MPF system based on the first-order Sagnac structure,the second-order Lyot-Sagnac structure and the second-order SolcSagnac structure,respectively.Simulation has been carried out to obtain the output spectrum,and on this basis,we have proposed an MPF based on the second-order LyotSagnac structure.Experimental results show that this MPF can effectively improve the signal isolation of the frequency response.The MPF based on the second-order SolcSagnac structure is also proposed and experimentally demonstrated,and the results show that this MPF can realize free switching of the passbands,and the number of MPF's passbands can be selectable by adjusting the polarization controller in the Sagnac loop MPFs with single-passband,dual-passband and the multi-passband have been realized in the experiment.Then,we have explored the periodic incoherent MPF based on the fiber ring structure.The characteristics of MPF based on fiber ring structure have been analyzed,simulated through Matlab and realized in the experiment.Temperature sensing system based on MPF with fiber ring and EDFA has been proposed and realized in the experiment,and the experimental results show that it can greatly improve the sensing resolution.Finally,the main work and research results are summarized,the shortcomings of the research are pointed out and the future research work is proposed.