Study On Photonic Generation Of Microwave Signals

With the rapid development of wireless communication and optical communication, microwave photonics has attractted great interest. As an important part of microwave photonics, photonic generation of microwave signals also has got much attention. Generating microwave signals with optical methods can overcome the shortage of the electronic methods. It has the advantage of low loss, simple structure and immunity to electromagnetic interference. The main topic of this thesis is the generation of single frequency microwave signals and ultra-wideband signals with optical methods.Firstly, the concepts of microwave photonics and the technology of photonic generation of microwave signals are introduced. Then, generation of single frequency microwave signals is studied. Optical frequency doubling method based on external modulation is achieved and applied in a radio-over-fiber system. It improves the transmission performance of the system. After that, the ultra-wideband communication technology and the generation of ultra-wideband signals are researched. And then, a single-source microwave photonic filter based on a Sagnac interferometer, which has certain potential applications, is carried out with theoretical analysis and experimental results. Ultra-wideband signals are generated by shaping Gaussian pulses with this bandpass filter. On this basis, a two-source microwave photonic bandpass filter is designed to generate ultra-wideband signals, with which the generated ultra-wideband signals comply with the frequency mask defined by Federal Communications Commission better. Finally, the summary and future research is given.Two new methods of photonic generation of ultra-wideband signals are designed and realized in this thesis. They are carried out in both theory and experiment. It has certain theoretical and application significance and engineering value.