Accelerating the phase demodulation process for heterodyne Φ-OTDR using spatial phase shifting

Area of Science:

• Optoelectronics
• Signal Processing
• Photonics

Background:

• Heterodyne-detection-based phase-sensitive optical time-domain reflectometer (φ-OTDR) systems are crucial for various sensing applications.
• Efficient phase demodulation is essential for real-time data acquisition and analysis in φ-OTDR.
• Current methods face computational complexity, limiting processing speed.

Purpose of the Study:

• To propose an effective orthogonal signal generation method for heterodyne-detection-based φ-OTDR systems.
• To accelerate the phase demodulation process in φ-OTDR.
• To reduce the computational complexity of phase demodulation for distributed acoustic sensing (DAS).

Main Methods:

• The proposed method utilizes spatial phase shifting techniques.
• Orthogonal signals are generated by exploiting the relative phase difference between adjacent spatial sampling channels.
• Basic algebraic calculations are employed for signal generation.

Main Results:

• The method achieved over 100% computation speed improvement compared to conventional approaches.
• A slight trade-off in phase demodulation performance was observed.
• Simulations and experimental results validated the proposed method's effectiveness.

Conclusions:

• The developed orthogonal signal generation method significantly accelerates phase demodulation in φ-OTDR.
• This technique offers a potential solution for enhancing the performance of distributed acoustic sensing systems.
• The method reduces computational complexity, making φ-OTDR more efficient for practical applications.