Analysis and mitigation of the carrier phase delay effect of the digital phase generated carrier algorithm

We present an improved digital phase generated carrier algorithm based on the synchronous carrier restoration (SCR) method to mitigate the carrier phase delay effect. The most distinguishing feature of this method is that it directly picks up the carrier signal information (frequency and phase) from the interference signal and synchronically accomplishes the processing of carrier signal restoration. In comparison to the traditional method, which adopts the initial carrier signal, total-harmonic-distortion with SCR is only 0.091%, lower than the traditional SCR of 18.38%, and the signal-to-noise ratio increases by 29 dB. Further, we derived the analytic expression of the distortion component and verified it by experiments. This technique may be potentially applied to a long-distance large-scale distributed fiber-optic interferometric sensor array.