Enhancement of the Performance and Data Processing Rate of an Optical Frequency Domain Reflectometer Distributed Sensing System Using A Limited Swept Wavelength Range

A novel optical frequency domain reflectometer (OFDR) processing algorithm is proposed to enhance the measurable range and data processing rate using a narrow swept spectrum range and reducing the time consuming of the process distributed sensing results. To reduce the swept wavelength range and simultaneously enhance strain measurable range, the local similarity characteristics of Rayleigh scattering fingerprint spectrum is discovered and a new similarity evaluation function based on least-square method is built to improve the data processing rate and sensing performance. By this method, the strain measurable range is raised to 3000 µε under a highest spatial resolution of 3 mm when the swept spectrum range is only 10 nm and the data processing rate is improved by at least 10 times. Experimental results indicate that a nonlinearity of less than 0.5%, a strain resolution of better than 10 µε, a repeatability at zero strain of below ±0.4 GHz and a full-scale accuracy is lower than 0.85 GHz under a highest spatial resolution of 3 mm can be achieved. Advantages of this method are fast processing rate, large strain measurable range, high SNR, and applicability with current OFDR systems.

[1]  Ronald Rousseau,et al.  Requirements for a cocitation similarity measure, with special reference to Pearson's correlation coefficient , 2003, J. Assoc. Inf. Sci. Technol..

[2]  Kun Liu,et al.  Note: Improving distributed strain sensing sensitivity in OFDR by reduced-cladding single mode fiber. , 2016, The Review of scientific instruments.

[3]  H. Kiers.  Weighted least squares fitting using ordinary least squares algorithms , 1997 .

[4]  Joris Degrieck,et al.  Dynamic Strain Measurements on Automotive and Aeronautic Composite Components by Means of Embedded Fiber Bragg Grating Sensors , 2015, Sensors.

[5]  Duncan C. Wyllie,et al.  Civil engineering applications , 2017, Tire Waste and Recycling.

[6]  António Barrias,et al.  A Review of Distributed Optical Fiber Sensors for Civil Engineering Applications , 2016, Sensors.

[7]  Tae-Jung Ahn,et al.  Suppression of nonlinear frequency sweep in an optical frequency-domain reflectometer by use of Hilbert transformation. , 2005, Applied optics.

[8]  Xiaoyi Bao,et al.  Long-Range High Spatial Resolution Distributed Temperature and Strain Sensing Based on Optical Frequency-Domain Reflectometry , 2014, IEEE Photonics Journal.

[9]  A. Hall.  The Method of Least Squares , 1872, Nature.

[10]  Sasi Jothibasu,et al.  Strain monitoring using distributed fiber optic sensors embedded in carbon fiber composites , 2018, Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.

[11]  Liang Chen,et al.  Distributed Temperature and Strain Discrimination with Stimulated Brillouin Scattering and Rayleigh Backscatter in an Optical Fiber , 2013, Sensors.

[12]  Stephen T. Kreger,et al.  High-resolution extended distance distributed fiber-optic sensing using Rayleigh backscatter , 2007, SPIE Smart Structures and Materials + Nondestructive Evaluation and Health Monitoring.