Research On Optical Filter Spectral Response Measurement Based On Time Frequency Signal Excitation

Optical filter is one of fundamental optical devices in the optical link,and the spectral response of filters presents the information about bandwidth and central frequency.Therefore,accurate measurement of the spectral response of filters is critical for evaluating and optimizing the optical link.The measurement results of optical methods have low resolution.By utilizing microwave photonics,the above-mentioned disadvantage can be overcome.Microwave photonics combines the advantages of the optical domain and the electrical domain,which is of great significance.In this thesis,we propose methods to measure the spectral response of optical filters based on time frequency signal excitation.The main contents are summarized as follows:An approach to measuring the spectral response of optical filters based on single-sideband modulation is studied.Analysis,simulation and experiment are implemented.In the simulation,the spectral response of the Gaussian band-stop optical filter in the 20GHz range is given.The method is verified in experiment.The spectral response of the stimulated Brillouin loss spectrum of the non-zero dispersion-shifted fiber is given and measurement frequency range is 2GHz.The measurement resolution based on the single-sideband modulation is related to the electrical signal frequency-swept stepping.The measurement range is small,which is limited by the bandwidth of the microwave source.The measurement efficiency is low and can be used to the spectral response measurement of the band-stop optical filter.An approach to measuring the spectral response of optical filters based on pseudorandom periodic signal excitation is proposed.Analysis,simulation and experiment are implemented.In the simulation,a pseudorandom sequence with a code rate of 12.7Gbit/s is used to measure the spectral response of the fiber Bragg grating's reflection spectrum.The measurement frequency range is 200GHz.The validity of the method is verified in experiment.The spectral response of the optical filter is given.The measurement frequency range is over than 20 GHz.The measurement resolution based on the pseudorandom periodic signal excitation is related to the fundamental frequency of the pseudorandom periodic signal.The measurement range is wide.The measurement efficiency is high,and can be used to the spectral response measurement of optical filters with any response.An approach to measuring the spectral response of optical filters based on non-periodic signal excitation is proposed.Analysis and simulation are implemented.In simulation,non-periodic signal with a code width of 50ps is used to measure the spectral response of the fiber Bragg grating's transmission spectrum.The measurement frequency range is 150GHz.The measurement resolution based on non-periodic signal excitation is related to the resolution of the observation instruments.The measurement range is wide.The measurement efficiency is high,and can be used to the spectral response measurement of the band-stop optical filter.