LAUSR

Abstract. The phase-generated carrier (PGC) modulation–demodulation technique is one of the key signal demodulation schemes in interferometric fiber-optic sensing systems. The phase modulation depth (C) and carrier phase delay (θ) are critical factors affecting the performance of the demodulation algorithm. We present an improved PGC demodulation algorithm that eliminates the influence of carrier phase delay by utilizing the sum of multiple harmonic squares. By constructing a perfect square expression containing Bessel functions from harmonic signals and applying Bessel function transformation equations, the impact of phase modulation depth is also removed, enabling more accurate signal demodulation. The validity of the algorithm is verified through simulations and experiments. This research provides a valuable reference for signal processing in practical fiber-optic sensor applications.