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Journal of Lightwave Technology

Journal of Lightwave Technology


  • Vol. 27, Iss. 21 — Nov. 1, 2009
  • pp: 4884–4891

Directional Bend Sensing With a CO$_{2}$-Laser-Inscribed Long Period Grating in a Photonic Crystal Fiber

Long Jin, Wei Jin, and Jian Ju

Journal of Lightwave Technology, Vol. 27, Issue 21, pp. 4884-4891 (2009)

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In this paper, we present a directional bend sensor based on a long period grating (LPG) formed by introducing periodic grooves along one side of a photonic crystal fiber (PCF) with a focused ${\hbox {CO}}_{2}$ laser beam. A bend sensitivity of 2.26 nm/m$^{-1}$ within a range of $-$5 $\sim +$5 m$^{-1}$ is experimentally demonstrated. Numerical simulation suggests that the directional response is the result of asymmetric cladding geometry resulted from collapse and/or deformation of air holes and asymmetric material-index modulation caused by one-sided illumination of the ${\hbox {CO}}_{2}$ laser beam. The sensitivity could be further enhanced by increasing the area of the air-silica photonic crystal cladding and optimizing the size of individual air holes. The easy fabrication process and good linear response of the proposed sensor make it a suitable candidate for structural shape sensing in harsh environments.

© 2009 IEEE

Long Jin, Wei Jin, and Jian Ju, "Directional Bend Sensing With a CO$_{2}$-Laser-Inscribed Long Period Grating in a Photonic Crystal Fiber," J. Lightwave Technol. 27, 4884-4891 (2009)

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