• Chinese Optics Letters
  • Vol. 19, Issue 9, 090601 (2021)
Fangcheng Shen1, Xuewen Shu2, Kaiming Zhou3, Haiming Jiang1, Hongyan Xia1, Kang Xie1、*, and Lin Zhang3
Author Affiliations
  • 1State Key Laboratory of Precision Electronic Manufacturing Technology and Equipment, School of Electromechanical Engineering, Guangdong University of Technology, Guangzhou 510006, China
  • 2Wuhan National Laboratory for Optoelectronics & School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074, China
  • 3Institute of Photonic and Technologies, Aston University, Birmingham B4 7ET, UK
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    DOI: 10.3788/COL202119.090601 Cite this Article Set citation alerts
    Fangcheng Shen, Xuewen Shu, Kaiming Zhou, Haiming Jiang, Hongyan Xia, Kang Xie, Lin Zhang. Compact vector twist sensor using a small period long period fiber grating inscribed with femtosecond laser[J]. Chinese Optics Letters, 2021, 19(9): 090601 Copy Citation Text show less
    Schematic of long period fiber grating.
    Fig. 1. Schematic of long period fiber grating.
    Transmission spectrum of the fabricated grating measured with un-polarized light. Inset shows the photograph of the grating, where the grating length is indicated by the red light scattered out of the fiber, and the interval of the ruler is millimeters (mm).
    Fig. 2. Transmission spectrum of the fabricated grating measured with un-polarized light. Inset shows the photograph of the grating, where the grating length is indicated by the red light scattered out of the fiber, and the interval of the ruler is millimeters (mm).
    Transmission spectra of the fabricated grating with two orthogonal input polarizations (P1 and P2).
    Fig. 3. Transmission spectra of the fabricated grating with two orthogonal input polarizations (P1 and P2).
    Schematic of the experimental setup for twist sensing. SC, super-continuum source; PC, polarization controller.
    Fig. 4. Schematic of the experimental setup for twist sensing. SC, super-continuum source; PC, polarization controller.
    Evolution of (a) transmission spectra (peak positions are denoted by black circles), (b) peak intensity, (c) peak wavelengths with increasing twist angle, and (d) wavelength-interrogated twist sensitivity calculated from the fitted function at each measurement point.
    Fig. 5. Evolution of (a) transmission spectra (peak positions are denoted by black circles), (b) peak intensity, (c) peak wavelengths with increasing twist angle, and (d) wavelength-interrogated twist sensitivity calculated from the fitted function at each measurement point.
    Evolution of (a) peak intensity and (b) peak wavelength with increased strain, when the grating was pre-twisted with an angle of 10 deg (blue circles), 30 deg (black rectangles), and 50 deg (magenta triangles). The linear fitting of the evolution is depicted by red lines.
    Fig. 6. Evolution of (a) peak intensity and (b) peak wavelength with increased strain, when the grating was pre-twisted with an angle of 10 deg (blue circles), 30 deg (black rectangles), and 50 deg (magenta triangles). The linear fitting of the evolution is depicted by red lines.
    Evolution of (a) peak intensity and (b) peak wavelength with increased temperature, when the grating was pre-twisted with an angle of 10 deg (blue circles), 30 deg (black rectangles), and 50 deg (magenta triangles). The linear fitting of the evolution is depicted by red lines.
    Fig. 7. Evolution of (a) peak intensity and (b) peak wavelength with increased temperature, when the grating was pre-twisted with an angle of 10 deg (blue circles), 30 deg (black rectangles), and 50 deg (magenta triangles). The linear fitting of the evolution is depicted by red lines.
    InterrogationMethodSensitivityLength (mm)OrientationReference (year)
    IntensitySP-LPFG0.257 dB/deg2.8VectorThis work
    Cascaded LPFGs0.268dB/deg47.56 Scalar[28] (2018)
    ITO-coated TFBG0.274 dB/deg15 Vector[21] (2020)
    SMF-TFBG0.299 dB/deg10 Scalar[23] (2014)
    MMF-TFBG0.075 dB/degNAVector[22] (2014)
    Phase shift FBG0.088 dB/deg1.72Vector[27] (2016)
    Cascaded HLPFG0.0074 dB/deg58Vector[30] (2014)
    WavelengthSP-LPFG0.115 nm/deg2.8VectorThis work
    CO2 LPFG0.019 nm/deg20Vector[2] (2004)
    HLPFG0.067 nm/deg34Vector[5] (2017)
    Improved HLPFG0.029–0.11 nm/deg18–36Vector[37] (2020)
    Table 1. Sensing Performance of Fiber-Grating-Based Twist Sensors
    Fangcheng Shen, Xuewen Shu, Kaiming Zhou, Haiming Jiang, Hongyan Xia, Kang Xie, Lin Zhang. Compact vector twist sensor using a small period long period fiber grating inscribed with femtosecond laser[J]. Chinese Optics Letters, 2021, 19(9): 090601
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