Few-mode optical fiber based simultaneously distributed curvature and temperature sensing.

The few-mode fiber (FMF) based Brillouin sensing operated in quasi-single mode (QSM) has been reported to achieve the distributed curvature measurement by monitoring the bend-induced strain variation. However, its practicality is limited by the inherent temperature-strain cross-sensitivity of Brillouin sensors. Here we proposed and experimentally demonstrated an approach for simultaneously distributed curvature and temperature sensing, which exploits a hybrid QSM operated Raman-Brillouin system in FMFs. Thanks to the larger spot size of the fundamental mode in the FMF, the Brillouin frequency shift change of the FMF is used for curvature estimation while the temperature variation is alleviated through Raman signals with the enhanced signal-to-noise ratio (SNR). Within 2 minutes measuring time, a 1.5 m spatial resolution is achieved along a 2 km FMF. The worst resolution of the square of fiber curvature is 0.333 cm-2 while the temperature resolution is 1.301 °C at the end of fiber.

[1]  W. A. Gambling,et al.  Field deformation in a curved single-mode fibre , 1978 .

[2]  Ram Bilas Pachori,et al.  Raman optical fiber distributed temperature sensor using wavelet transform based simplified signal processing of Raman backscattered signals , 2015 .

[3]  L. Thévenaz,et al.  Simplex-coded BOTDA fiber sensor with 1 m spatial resolution over a 50 km range. , 2010, Optics Letters.

[4]  Z. Pan,et al.  Single-end simultaneous temperature and strain sensing techniques based on Brillouin optical time domain reflectometry in few-mode fibers. , 2015, Optics express.

[5]  M Taki,et al.  Hybrid Raman/Brillouin-optical-time-domain-analysis-distributed optical fiber sensors based on cyclic pulse coding. , 2013, Optics letters.

[6]  J. N. Ross,et al.  Distributed optical fibre Raman temperature sensor using a semiconductor light source and detector , 1985 .

[7]  G. Bolognini,et al.  Fiber-Optic Distributed Sensor Based on Hybrid Raman and Brillouin Scattering Employing Multiwavelength Fabry–PÉrot Lasers , 2009, IEEE Photonics Technology Letters.

[8]  S. Martín-López,et al.  Extending the Real Remoteness of Long-Range Brillouin Optical Time-Domain Fiber Analyzers , 2014, Journal of Lightwave Technology.

[9]  Liang Chen,et al.  Recent Progress in Distributed Fiber Optic Sensors , 2012, Sensors.

[10]  Songnian Fu,et al.  Few-mode fiber based distributed curvature sensor through quasi-single-mode Brillouin frequency shift. , 2016, Optics letters.

[11]  Hwa-Yaw Tam,et al.  Long-haul quasi-single-mode transmissions using few-mode fiber in presence of multi-path interference. , 2015, Optics express.

[12]  Determination of bending-induced strain in optical fibers by use of quantitative phase imaging. , 2002, Optics letters.

[13]  S. M. Maughan,et al.  Simultaneous distributed fibre temperature and strain sensor using microwave coherent detection of spontaneous Brillouin backscatter , 2001 .

[14]  Hao Zhang,et al.  Two-dimensional bending vector sensing based on spatial cascaded orthogonal long period fiber. , 2012, Optics express.

[15]  Songnian Fu,et al.  Few-mode fiber based Raman distributed temperature sensing over 25 km with link optimization and wavelet-denoising , 2017, 2017 Conference on Lasers and Electro-Optics Pacific Rim (CLEO-PR).

[16]  David L. Donoho,et al.  De-noising by soft-thresholding , 1995, IEEE Trans. Inf. Theory.

[17]  Xun Hou,et al.  Compact bending sensor based on a fiber Bragg grating in an abrupt biconical taper. , 2015, Optics express.

[18]  T. Parker,et al.  A fully distributed simultaneous strain and temperature sensor using spontaneous Brillouin backscatter , 1997, IEEE Photonics Technology Letters.

[19]  Yongmin Jung,et al.  Adiabatically tapered splice for selective excitation of the fundamental mode in a multimode fiber. , 2009, Optics letters.

[20]  Luc Thévenaz,et al.  Distributed shape sensing using Brillouin scattering in multi-core fibers. , 2016, Optics express.

[21]  Alessandro Signorini,et al.  Optimized Hybrid Raman/Fast-BOTDA Sensor for Temperature and Strain Measurements in Large Infrastructures , 2014, IEEE Sensors Journal.

[22]  P. Shum,et al.  Temperature- and strain-insensitive curvature sensor based on ring-core modes in dual-concentric-core fiber. , 2016, Optics letters.

[23]  Luc Thévenaz,et al.  Modeling and evaluating the performance of Brillouin distributed optical fiber sensors. , 2013, Optics express.

[24]  T. Newson,et al.  Simultaneous temperature and strain measurement with combined spontaneous Raman and Brillouin scattering. , 2005, Optics letters.

[25]  Yongqin Yu,et al.  Micro-bending vector sensor based on six-air-hole grapefruit microstructure fiber using lateral offset splicing. , 2015, Optics express.

[26]  J E Antonio-Lopez,et al.  Compact fiber-optic curvature sensor based on super-mode interference in a seven-core fiber. , 2015, Optics letters.

[27]  Yoshiaki Yamauchi,et al.  Study of optical fibers strain-temperature sensitivities using hybrid Brillouin-Rayleigh system , 2014 .

[28]  Yunli Dang,et al.  Spatial-division multiplexed hybrid Raman and Brillouin optical time-domain reflectometry based on multi-core fiber. , 2016, Optics express.

[29]  H. Kee,et al.  All-fiber system for simultaneous interrogation of distributed strain and temperature sensing by spontaneous Brillouin scattering. , 2000, Optics letters.

[30]  G. Bolognini,et al.  Optical pulse coding in hybrid distributed sensing based on Raman and Brillouin scattering employing Fabry-Perot lasers. , 2010, Optics express.

[31]  R. Olshansky,et al.  Mode Coupling Effects in Graded-index Optical Fibers. , 1975, Applied optics.

[32]  J. Kahn,et al.  Principal Modes in Graded-Index Multimode Fiber in Presence of Spatial- and Polarization-Mode Coupling , 2009, Journal of Lightwave Technology.

[33]  Roger Haynes,et al.  Long period grating in multicore optical fiber: an ultra-sensitive vector bending sensor for low curvatures. , 2014, Optics letters.

[34]  Lingyun Xiong,et al.  Directional Bend Sensor Based on Re-Grown Tilted Fiber Bragg Grating , 2010, Journal of Lightwave Technology.

[35]  William Shieh,et al.  Measurement of distributed mode coupling in a few-mode fiber using a reconfigurable Brillouin OTDR. , 2014, Optics letters.

[36]  S. Martín-López,et al.  Brillouin optical time-domain analysis assisted by second-order Raman amplification. , 2010, Optics Express.

[37]  Marcelo A. Soto,et al.  Intensifying the response of distributed optical fibre sensors using 2D and 3D image restoration , 2016, Nature Communications.

[38]  R. Bernini,et al.  Bend-Induced Brillouin Frequency Shift Variation in a Single-Mode Fiber , 2013, IEEE Photonics Technology Letters.

[39]  B. Y. Kim,et al.  Few-mode fiber multi-parameter sensor with distributed temperature and strain discrimination. , 2015, Optics letters.

[40]  Songnian Fu,et al.  Spatial-division multiplexed Brillouin distributed sensing based on a heterogeneous multicore fiber. , 2017, Optics letters.

[41]  Joseba Zubia,et al.  Photonic crystal fiber interferometric vector bending sensor. , 2015, Optics letters.

[42]  S. Chi,et al.  Utilization of a dispersion-shifted fiber for simultaneous measurement of distributed strain and temperature through Brillouin frequency shift , 2001, IEEE Photonics Technology Letters.