Research Of Novel Microwave Photonic Filters

Microwave photonics is a new cross subject combined with the optical fiber technology and microwave technology. Microwave signal processing technology based on photonics method is an important part of the study of microwave photonics. Microwave photonic filter(MPF) is one of the most representative results of microwave photonics, whose function is the same as traditional microwave filter with the aid of photonic devices or optical subsystem. Microwave photonic filters have advantages as low loss, high bandwidth, resistance to electromagnetic interference, tunability and reconfigurable. In recent years, Microwave photonic filters gradually become the research frontier in the field of microwave photonic signal processing with high technology advancement and potential applications.The thesis focuses on the study of novel MPFs techniques, and it mainly consists the following contents:(a) We discussed the different kinds of ways to realize the microwave photonic filters and introduced the fundamentals and implementations of microwave photonic filters, which lies the theoretical foundation of the thesis.(b) An Infinite-Impulse Response(IIR) Microwave Photonic Filter(MPF) to obtain GHz level Free Spectral Range(FSR) with Multi-Longitudinal-Mode(MLM) laser as the source is proposed. By the periodic structure of degree of coherence of MLM laser, a stable IIR-MPF with FSR 0.59 GHz is realized and the relative fluctuation of the response curve is optimized to less than 2%.(c) We propose to a new single-wavelength, coherence-free microwave photonic notch filter with negative coefficients based on a Pol M and a PBI. It has the ability to generate a large tunable FSR frequency response and high SNR.