Research On Tunable And Reconfigurable Microwave Photonic Filter

Microwave photonics combines microwave technology and photonics,and draw two academic advantages,has broad application prospects.Microwave photonic filter as an important branch of microwave photonics,overcomes the bottleneck problem of radio frequency signal processing in the electric field compared with the traditional electronic filter.It can process the RF signal directly in the optical domain.Although the complexity of the filter is increased to a certain extent,the filter system has many advantages.Microwave photonic filter has the advantages of high bandwidth,low loss,small volume and anti-electromagnetic interference,but also has the characteristics of tunable and reconfigurable.In this paper,we mainly study the tunable and reconfigurable characteristics of microwave photonic filter,the main contents and work are as follows:(1)The research background and application of microwave photonics and microwave photonic filter,the classification of microwave photonic filter according to different characteristics,summarizes the research status of tunable and reconfigurable microwave photonic filter.(2)The basic principle of microwave photonic filter is described,and the examples of microwave photonic filter are introduced,and the theoretical analysis and numerical simulation of three kinds of optical fiber filters are given.(3)A tunable microwave photonic filter based on PCF delay element is proposed.Taking the photonic crystal fiber(PCF),filled with temperature sensitive liquid,as the delay unit of microwave photon filter.By adjusting the temperature change of PCF birefringence,makes two road through the PCF light delay difference change,realizes the tunable characteristics of filter.By controlling the Mach del modulator's dc bias voltage and polaroid rotation Angle,makes the filter tap coefficients change,realizes the reconfigurable characteristics.(4)A microwave photonic filter based on wavelength interval continuous tunable laser and MZ interferometer is proposed.Based on the filling PCF of Sagnac loop is taken as multiple wavelength laser frequency selective device,by adjusting the temperature,realizes wavelength spacing of laser continuous adjustable.It is used as the light source of microwave photonic filter,which can realize FSR continuous adjustable.After the light source connecting with MZ interferometer,regulating the interferometer arm length,can change the tap coefficient,realize reconfigurable.(5)A microwave photonic filter based on nonlinear polarization rotation effect laser and infinite impulse response is proposed.The multi-wavelength laser is taken as multi-wavelength light source,produced by nonlinear polarization rotation effect.Adjusting the laser polarization controller or temperature can change the laser wavelength interval.The output of the photoelectric detector is re-injected into the modulator to form an electrical signal feedback loop,and adjust the gain of the RF signal amplifier,which can effectivelyimprove the frequency response of the filter.