Research Of Widely Tunable Optoelectronic Oscillator Based On Chirped Phase-shifted Fiber Bragg Grating

With the human into the information age,people on the microwave signal quality requirements are getting higher and higher.Under these circumstances,as an ideal source of microwave signal generation,the optoelectronic oscillator(OEO)has received more and more attention and research.Compared with the traditional microwave oscillator,the microwave signal produced by the OEO has the advantages of wide bandwidth,tunable range,anti-electromagnetic interference and high spectral purity,so it is widely used in modern applications.In order to broaden the frequency tunable range of the OEO,a tunable OEO based on chirped phase-shifted fiber Bragg gratings(PS-FBG)is designed.Firstly,the characteristics of the reflective spectrum of a PS-FBG and the tunable range of the OEO based on the PS-FBG are theoretically.Then the reflection spectrum of Chirped PS-FBG and the tunable range based on Chirped PS-FBG are analyzed.Through simulation,the tunable range based on PS-FBG is 5 GHz to 55 GHz,and the sideband rejection ratio is 30 dB.The range of the OEO based on the chirped PS-FBG is expanded to 5 GHz to 155 GHz and the sideband suppression ratio is also increased to 40 dB.The tunable range of OEO is greatly improved.The noise characteristics of microwave signals generated by tunable OEO based on chirped PS-FBG are also studied in detail.In this paper,we make a reasonably theoretical derivation of the noise-related noise performance model in a small frequency range,and an improved noise theory model is analyzed in detail.The simulation results show that the improved noise model can reflect the noise performance in the OEO system comprehensively.