Performance Investigation of OFDR Sensing System with a Wide Strain Measurement Range

Spectrum registration and spatial calibration are presented and demonstrated in optical frequency domain reflectometry based sensing system for achieving a wide strain measurement range. In both dynamic and static measurement case, the feasibility of the proposed method is evaluated. First, spectrum registration is demonstrated to demodulate strain value, which increases the data acquisition rate dozens of times and also keep the high measurement range. A measurement rate up to 800 Hz is achieved. Second, the general difficulty in large strain measurement is analyzed. The combination of spatial calibration and spectrum registration is, therefore, proposed to reduce the mismatch of the spatial segments in the case of large strain variation. The local measurement spectrum segment extracted by a narrow box window for spectrum registration is proposed to maintain a high spatial resolution. Strain exceeding 7000 μϵ is demodulated with a gauge length of 5 mm accurately. Finally, graphic processing unit (GPU) technology is used to accelerate the data processing rate in the demodulation process, which makes it more hopeful for the practical application.