A High Performance Distributed Optical Fiber Sensor Based on Φ-OTDR for Dynamic Strain Measurement

A high-performance distributed optical fiber sensor based on phase-sensitive optical time-domain reflectometry (Φ-OTDR) for dynamic strain measurement has been proposed. In this newly designed system, ultraweak fiber Bragg gratings (UWFBGs) are sparsely embedded in the sensing fiber. Through an unbalanced 3 × 3 coupler structure, the reflected lights from two adjacent UWFBGs would be mixed with each other and then split into three parts for phase demodulation. Then, a novelty table-look-up scheme is introduced to precisely demodulate the frequency, amplitude, and phase of dynamic strain. Rayleigh back-scattering light is utilized to identify and locate the accurate position of vibration event between two adjacent UWFBGs. The experimental results show that the proposed system is capable of reconstructing the vibration with a linear intensity response of R2 = 0.9986 and a fiber length variation sensitivity of 117 pm/(Hz)1/2. Meanwhile, a wide frequency response band from 50 to 2075 Hz is achieved with high signal-to-noise ratio above 56 dB.

[1]  Qing Ye,et al.  Phase-sensitive OTDR system based on digital coherent detection , 2011, 2011 Asia Communications and Photonics Conference and Exhibition (ACP).

[2]  Xiaoyi Bao,et al.  Distributed Vibration Sensor Based on Coherent Detection of Phase-OTDR , 2010, Journal of Lightwave Technology.

[3]  Fei Peng,et al.  Ultra-long high-sensitivity Φ-OTDR for high spatial resolution intrusion detection of pipelines. , 2014, Optics express.

[4]  Gang-Ding Peng,et al.  Distributed acoustic mapping based on interferometry of phase optical time-domain reflectometry , 2015 .

[5]  Fei Peng,et al.  Real-Time Position and Speed Monitoring of Trains Using Phase-Sensitive OTDR , 2014, IEEE Photonics Technology Letters.

[6]  H. Cai,et al.  Characteristics and Explanations of Interference Fading of a $\phi $ -OTDR With a Multi-Frequency Source , 2013, Journal of Lightwave Technology.

[7]  Yixin Zhang,et al.  The performance limit of Φ-OTDR sensing system enhanced with ultra-weak fiber Bragg grating array , 2015, International Conference on Optical Instruments and Technology.

[8]  Y. Rao,et al.  Coherent Φ-OTDR based on I/Q demodulation and homodyne detection. , 2016, Optics express.

[9]  Xuping Zhang,et al.  Performance improvement for long-range BOTDR sensing system based on high extinction ratio modulator , 2014 .

[10]  Chenyuan Hu,et al.  A Novel Interrogation System for Large Scale Sensing Network With Identical Ultra-Weak Fiber Bragg Gratings , 2014, Journal of Lightwave Technology.

[11]  Fan Zhu,et al.  Active Compensation Method for Light Source Frequency Drifting in $\Phi $ -OTDR Sensing System , 2015, IEEE Photonics Technology Letters.

[12]  R. Priest,et al.  Analysis of fiber interferometer utilizing 3 × 3 fiber coupler , 1982 .

[13]  Juan C Juarez,et al.  Field test of a distributed fiber-optic intrusion sensor system for long perimeters. , 2007, Applied optics.

[14]  Zuyuan He,et al.  Long-Range Distributed Vibration Sensing Based on Phase Extraction From Phase-Sensitive OTDR , 2016, IEEE Photonics Journal.

[15]  Michael A. Davis,et al.  Fiber grating sensors , 1997 .

[16]  Xuping Zhang,et al.  Improved Φ-OTDR Sensing System for High-Precision Dynamic Strain Measurement Based on Ultra-Weak Fiber Bragg Grating Array , 2015, Journal of Lightwave Technology.

[17]  Gang-Ding Peng,et al.  Distributed OTDR-interferometric sensing network with identical ultra-weak fiber Bragg gratings. , 2015, Optics express.

[18]  Trevor P. Newson,et al.  A distributed optical fibre dynamic strain sensor based on phase-OTDR , 2013 .

[19]  Yixin Zhang,et al.  Enhanced Φ-OTDR system for quantitative strain measurement based on ultra-weak fiber Bragg grating array , 2016 .

[20]  Jaehong Park,et al.  Analyzing OTDR Measurement Data Using the Kalman Filter , 2008, IEEE Transactions on Instrumentation and Measurement.

[21]  S. Faralli,et al.  A Cost-Effective Distributed Acoustic Sensor Using a Commercial Off-the-Shelf DFB Laser and Direct Detection Phase-OTDR , 2016, IEEE Photonics Journal.

[22]  Xiaoyi Bao,et al.  Modulated pulses based distributed vibration sensing with high frequency response and spatial resolution. , 2013, Optics express.

[23]  Yan Feng,et al.  Combination of Phase-Sensitive OTDR and Michelson Interferometer for Nuisance Alarm Rate Reducing and Event Identification , 2016, IEEE Photonics Journal.

[24]  Steven L. Garrett,et al.  A symmetric analogue demodulator for optical fiber interferometric sensors , 1991, [1991] Proceedings of the 34th Midwest Symposium on Circuits and Systems.