High-performance PGC algorithm for a Φ-OTDR system based on multi-carrier mixing

Area of Science:

• Optical Engineering
• Signal Processing
• Fiber Optic Sensors

Background:

• Distributed fiber sensing systems, like Φ-OTDR, face accuracy limitations due to modulation depth, carrier phase delay, and laser intensity disturbances.
• These disturbances hinder high-accuracy vibration sensing in complex environments.

Purpose of the Study:

• To develop a high-performance phase-generated carrier (PGC) demodulation algorithm for distributed fiber sensing.
• To overcome limitations of conventional PGC algorithms by suppressing environmental disturbances.

Main Methods:

• Proposed a novel multi-carrier mixing (PGC-MCM) algorithm.
• Utilized mathematical logic operations between mixed carrier signals and interference signals for phase reconstruction.
• Conducted experiments to validate performance under varying vibration conditions.

Main Results:

• The PGC-MCM algorithm accurately reconstructs phase signals and suppresses disturbances.
• Achieved high-fidelity recovery of vibration signals with varying frequencies and amplitudes.
• Demonstrated excellent linearity and noise immunity with THD of -66.32 dB, SINAD of 54.74 dB, and amplitude error rate of 0.46%.

Conclusions:

• The PGC-MCM algorithm offers a robust solution for high-accuracy distributed optical fiber sensing.
• The proposed method significantly improves vibration sensing performance in challenging conditions.
• This advancement holds strong potential for practical applications requiring precise fiber optic sensing.