Frequency Measurement Of High Frequency Electromagnetic Wave Based On Optical Frequency Comb And Optical Fourier Transform

High frequency electromagnetic wave frequency measurement and analysis plays a significant role in civil and defense applications.Recently,big challenges emerge as the operation frequency and frequency hopping rate in frequency-hopping communication and electronic warfare increase rapidly.Thanks to the inherent high speed and large bandwidth offered by optics,a series of photonic approaches and solutions are proposed for measuring the frequency of microwave signals in recent years.The fast frequency measurement of high frequency electromagnetic wave(1-100GHz)is the main research content.A novel approach of frequency measurement based on optical Fourier transform spectrum analysis completed by fiber dispersion and optical frequency comb is proposed.The design mainly takes advantage of the spectrum analysis function of optical Fourier transform and the frequency scale function of optical frequency comb.The measured frequency calculated by optical Fourier transform is more accurate by the correction of the optical frequency comb.The new scheme of frequency measurement is verified by simulation.At the same time,the impact factors of frequency measurement accuracy are analyzed.The main works are taken in the following aspects:The demand of microwave frequency measurement in real time is analyzed.This is why the research work was done.Two aspects of basic theory supporting for frequency measurement are described by means of schemes and analyzed by mathematics.On the one hand,the typical optical frequency comb scheme is introduced in detail,and the mathematical analysis of its principle is carried out.On the other hand,the longitudinal descriptions of frequency measurement technology by optical Fourier transform are carried out.The generation schemes of optical Fourier transform are introduced in this thesis.Meanwhile,detailed analyses of spectrum analysis and frequency measurement by optical Fourier transform are done in theory,and the principle of time lens which is the key part of optical Fourier transform is introduced in detail and the theoretical analysis of time lens is made simultaneously.And the frequency measurement based on optical Fourier transform is verified by experiment.This design scheme is verified by simulation using OptiSystem.The purpose of high frequency electromagnetic wave(1-100GHz)real-time frequency measurement is achieved.Meanwhile,the accuracy of frequency measurement has been improved qualitatively.And the influence of high-order dispersion on frequency measurement accuracy is analyzed,and the corresponding solution is proposed in this thesis.In summary,this thesis starts from optical frequency comb and optical Fourier transform based on time lens,and a novel real-time frequency measurement scheme is proposed.The design is verified by simulation,and the results show that the real-time frequency measurement of 1-100GHz microwave can be completed by this design with high accuracy.In the meantime,the impact factors of frequency measurement accuracy are analyzed,and the corresponding solution is proposed.