Research On Microwave Photonic Frequency Measurement Based On Integrated Silicon Waveguide Optical Filter

Microwave frequency measurement is one of the important branchs of the microwave photonic signal processing.Many microwave photonic frequency measurement systems based on discrete optical fiber devices have been reported.However,their applications are limited due to the shortcomings such as large size,high energy consumption and high cost.In recent years,with the development of microwave photonic integration technology,the integrated microwave photonic frequency measurement systems have been attracted attention.But the constraints between the large measurement range and high measurement accuracy still need to be solved.In this thesis,microwave photonic frequency measurement systems based on Silicon nitride integrated Mach-Zehnder interference filters were investigated theoretically and experimentally.First,the background of microwave photonic frequency measurements,and three different methods of microwave frequency measurements based on microwave photonic technologies were given.Then,a microwave photonic frequency measurement system using optical power mapping method based on integrated ring assisted Mach-Zehnder interferometer(RAMZI)chip was proposed.A automatic control software of the frequency measurement system was designed using Labview.The performances of the RAMZI chip were measured and analyzed.Due to the complementarity of the spectra of the two RAMZI's outputs,a highly linear amplitude comparison function(ACF)for estimating the microwave frequency was obtained.Experiment results proved that the system can achieve a narrow-range measurement with high-precision in frequency range of 5 GHz,root mean square error(RMSE)of less than 30 MHz was achieved.The system can also achieve a wide-range measurement with low-precision in a frequency range of 11 GHz,in which the measured RMSE is less than 102 MHz.In order to further expand the measurement range,a multi-band measurement scheme was proposed,in which the frequency measurement range is increased to 40 GHz while the RMSE is about 37 MHz.In addition,based on the asymmetric Mach-Zehnder interferometer(AMZI),a microwave power mapping frequency measurement system was designed.The measurement range and measurement accuracy of the system could be characterized by different ACFs.The theoretical analysis and simulation results showed that the system could maintain high measurement accuracy while expanding the measurement range.