The influence of parameter estimation error on PGC demodulation in optical fiber sensor

When using the phase generated carrier (PGC) method to demodulate the collected fiber optic hydrophone signal, there may be a certain error in the estimation process of the parameters in the system, which will cause a certain deviation between the demodulated signal and the original signal. In order to analyze the influence of these errors on the demodulation results, the demodulated signal is evaluated from the frequency and amplitude of the maximum total harmonic loss (THD) THD max and the maximum relative amplitude error (RAE) RAE max that vary with the initial phase.The simulation analysis is compared with the actual test results, and the influence of the construction parameter error on the test results is evaluated in the use of the construction division method.It is found that the second harmonic term in the additional intensity modulation has a certain impact on the demodulation. After the second harmonic term is added to the simulation, the actual test results are in good agreement with the simulation results.