Interferometeric Fibre Optic Signal Processing Based on Wavelet Transform for Subsea Gas Pipeline Leakage Inspection

A fiber-optic interferometric method for subsea gas pipeline leakage detection simulation test was conducted in underwater waveguide lab. The leakage signal with simultaneous phase variation is interferometrically measured based on Sagnac interferometer configuration. The phase signal extraction was by the demodulation technique based on phase generated carrier circuit. The wavelet transform was performed at each spatial resolution of interfere metric signal. It suppressed noise and improve optical signal SNR (signal to noise ratio). Underwater test discussed the possibility of fiber optic interferometer detection underwater pipeline leak event. The results showed it improved null frequency point capture ability in frequency domain and localization accuracy.