Shi L,Tu X H,Shan Z Y,et al. Research on Acoustic Sensing of Fiber Bragg Grating based on Edge Filter Detection[J]. Study on Optical Communications,2023(2):40-44.
Shi L,Tu X H,Shan Z Y,et al. Research on Acoustic Sensing of Fiber Bragg Grating based on Edge Filter Detection[J]. Study on Optical Communications,2023(2):40-44. DOI: 10.13756/j.gtxyj.2023.02.007.
Research on Acoustic Sensing of Fiber Bragg Grating based on Edge Filter Detection
The strain sensitivity of bare fiber grating under the action of acoustic wave is too low
which is difficult to detect the effective reflection wavelength change. In this paper
the longitudinal sensing of fiber grating is used as a model
and a layer of thickness far exceeding the inner diameter of the fiber is coated around the grating. Low Young's modulus cylindrical coating is used to increase the strain sensitivity of the fiber grating. We also use the linear region of the reflection spectrum of the phase-shift grating as the edge of the edge filtering method to improve the sensitivity of laser detection. Transmission matrix method is then applied in the simulation to analysis the reflection spectrum of grating and reflectance curve of laser. The simulation results show that the strain sensitivity of the longitudinal sensing model of acoustic wave is better than that of the transverse sensing model. The coating layer with low Young's modulus can significantly improve the strain sensitivity of the grating. Under the action of acoustic wave with frequency lower than 1.7 kHz.The longitudinal sensing sensitivity of the fiber grating coated with polyurethane coating reaches 6.1 nm/MPa
which is 381 times higher than that of the bare fiber grating. Combined with the phase-shift grating reflection spectrum linear region
the comprehensive sensitivity is improved by 2 203.6 times
effectively improving the acoustic wave detection sensitivity of the grating.
Liu Y Q, Guo Z Y, Liu Z G, et al. High-sensitivity Fiber Grating Pressure Sensor with Polymer Jacket[J]. Chinese Journal of Lasers, 2000, 27(3): 212-214.
Zhang Y, Feng D J, Liu Z G, et al. High-sensitivity Pressure Sensor Using a Shielded Polymer-coated Fiber Bragg Grating[J].Photonics Technology Letters, 2001, 13(6): 618-619.
Li C, Peng X B, Zhang H, et al. A Sensitivity-enhanced Flexible Acoustic Sensor Using Side-polished Fiber Bragg Grating[J].Measurement, 2018, 117(5): 252-257.
Hocker G B. Fiber Optic Acoustic Sensors with Composite Structure: an Analysis[J].Applied Optics, 1979, 18(21): 3679-3683.
Tu X H, Geng S G. Sensing Characteristics of Tapered Fiber Grating[J]. Chinese Journal of Quantum Electronics, 2018, 35(2): 247-251.
赵鑫彤. 基于光纤光栅的医疗超声波传感器研究[D]. 北京: 北京邮电大学, 2016.
Zhao X T. A Reaserch of Medical Ultrasonic Sensor based on Fiber Bragg Grating[D]. Beijing: Beijing University of Posts and Telecommunications, 2016.
Cusano A, Addio D, Cutolo A, et al. Plastic Coated Fiber Bragg Gratings as Hign Sensitivity Hydrophones[C]//Sensors Conference 2006. Daegu, South Korea: IEEE, 2006: 166-169.
Tu X H, Zhao Y C. Temperature and Stress Sensing Characteristics of Symmetrically Fused Tapered Fiber Grating[J]. Acta Phys. Sin, 2019, 68(24): 184-191.
Ma W C, Chen S H, Zhao K, et al. Phase-shifted Fiber Bragg Grating Strain Sensor Demodulated by Edge Filter[J]. Chinese Journal of Lasers, 2013, 40(9): 125-129.
Li D M, Chen J, Ge H L, et al. Water Sound Sensor Using the Optical Fiber Grating Sensitivity Enhanced Through Side Pressure and End Surface Pulling[J]. Acta Optica Sinica, 2012, 32(5): 37-44.
Minardo A, Cusano A, Bernini R, et al. Response of Fiber Bragg Grating to Longitudinal Ultrasonic Waves[J]. IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, 2005, 52(2): 304-312.