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    A new orthogonal signal generation method speeds up phase demodulation in phase-sensitive optical time-domain reflectometer systems. This technique enhances computation speed for distributed acoustic sensing, simplifying complex phase demodulation procedures.

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    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.