The Research On Frequency Measurement Based On Microwave Photonics And Photonic Integration Technology

Instantaneous frequency measurement plays an essential role in modern radar and communication.Traditional electrical instantaneous frequency measurement can only provide a limited measurement range due to the electronic bottleneck.Microwave photonic technology has the advantages of large operation bandwidth,low transmission loss,and immunity to electromagnetic interference,which has attracted great attentions in recent years from researchers.Microwave photonic frequency measurement technology has also got greatly developed.In addition,featuring small size,high stability,and ultra-low power consumption,integrated microwave photonics has become one of the most important future development directions of microwave photonic.This dissertation investigates the microwave photonic frequency measurement technology and the implemention through photonic integration technology.The theoretical analysis and the simulation results are given in the dissertation.The detailed works are as follows:1.The research background,significance and status of microwave photonic frequency measurement technology are introduced.The working principles of key devices in the schemes are analyzed and the theoretical models are given.The periodic fading caused by dispersion of optical fiber is introduced in detail,and the simulation is also performed.2.A microwave frequency measurement scheme based on fixed compensation of phase modulator(PM)and Mach-Zehnder modulator(MZM)is designed.The scheme uses the dispersion effect of two different modulation signals in single-mode fiber to obtain two power fading curves with different growth trends,which can be used to construct the amplitude comparison function(ACF)for frequency measurement.Meanwhile,by introduing two optical signals for compensation,the frequency measurement range of the system can be improved.The simulation results indicate that the designed scheme can achieve a frequency measurement accuracy of 0.15 GHz in the range of 0.5-19 GHz.3.A microwave frequency measurement scheme based on Dual Polarization Quadrature Phase Shift Keying(DP-QPSK)Modulator and Dense Wavelength Division Multiplexer(DWDM)is designed.The scheme uses DP-QPSK modulator to modulate two-channel carrier suppressed single-sideband signals and polarization multiplexing,and uses the roll-off area of one channel of DWDM to measure the frequency by the characteristics of different power fading at different frequencies.The system only needs one laser and one channel of DWDM,which simplifies the link structure.By building a microwave photonic simulation link,the feasibility of the scheme is verified,and the simulation results indicate that the designed scheme has a frequency measurement accuracy of 0.4 GHz in the frequency measurement range of 0-30 GHz.4.A microwave frequency measurement scheme based on optical frequency comb(OFC)down conversion and ACF is designed.The scheme uses cascaded modulators to generate a flat optical frequency comb,and after passing through DWDM,a stepped optical comb is formed.By coupling the flat OFC and modulation signal,and the stepped OFC and modulation signal respectively,the frequency is down-converted respectively.By comparing the power changes of the intermediate frequencies,the unknown signal frequencies can be calculated.The scheme only needs one set of OFC,and the frequency measurement range can be doubled by using a frequency shifter,and the 90° optical mixer can be used to achieve image rejection to solve a kind of frequency ambiguity.The simulation results indicate that the designed scheme can achieve a large bandwidth of 0-60 GHz and a frequency measurement accuracy of 250 k Hz.5.The research background and research status of photonic integration technology home and abroad are studied,and the feasibility of the three designed schemes based on photonic integration is verified by using Ansys Lumerical.