| The Microwave photonic filter is a kind of basic research content in microwave photonics field.In this paper,the finite impulse response microwave photonic filter based on an optical frequency comb is systematically studied by means of theoretical derivation,simulation analysis and experimental research.These efforts are of great theoretical and realistic significance for both basic and applied research of microwave photonic filters.The detailed contents include the followings:1.The basic principle of finite impulse response microwave photonic filter based on an optical frequency comb is theoretically deduced.Furthermore,the mathematical model of the finite impulse response microwave photonic filter is established,and the influence of system characteristic parameters on the transfer function of the filter is analyzed.2.The finite impulse response microwave photonic filter based on an optical frequency comb is simulated.The electro-optic modulation modes such as single sideband modulation,carrier suppressed single sideband modulation,double sideband modulation and carrier suppressed double sideband modulation are studied by means of Optisystem and MATLAB.Two kinds of shapers based on MATLAB and optical attenuators are constructed.The free spectrum range of the filter based on MATLAB shaper is up to 10 GHz and the 3d B bandwidth is up to 250 MHz.The free spectrum ranges of the filters obtained based on the optical attenuator shaper are 8.2GHz and 13.5GHz respectively,and the corresponding 3d B bandwidths are 0.5GHz and 2.3GHz respectively.3.A finite impulse response microwave photonic filter based on an optical frequency comb is obtained experimentally.The stability of the laser source is tested.The repetition frequency of the optical frequency comb is doubled from 12.5GHz to 25 GHz by an timedelay interferometer.Based on a dual drive Machzendel modulator,the carrier suppressed double sideband,carrier unsuppressed double sideband and carrier unsuppressed single sideband are realized.Two kinds of filter with flat top and Gaussian passband shape are obtained in the experiment.The filter order is up to 256 and the bandwidth of 3d B is up to 300 MHz. |
