Real-time sensing approach for optical frequency domain reflectometry using an FPGA-based high-speed demodulation algorithm

Optical frequency-domain reflectometry (OFDR) is pivotal in structural health monitoring. However, real-time sensing remains challenging owing to the demodulation speed limitations imposed by hardware constraints and intricate processes. To address this, we propose an FPGA-based high-speed demodulation algorithm employing a 2D FFT and frequency-domain cross-correlation algorithm. The experiments demonstrate that our system achieves the following specifications: sensing length of 50 m, spatial resolution of 6.4 mm, strain resolution of 16<i>μ</i> <i>ε</i>, strain range of ±2000<i>μ</i> <i>ε</i>, and real-time sensing rate of 24 Hz. We present what we believe is a novel approach for real-time OFDR sensing with limited hardware resources and potential broader applications.