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Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 21, Iss. 10 — May. 20, 2013
  • pp: 11853–11861

In-fiber directional coupler for high-sensitivity curvature measurement

J. R. Guzman-Sepulveda and D. A. May-Arrioja  »View Author Affiliations

Optics Express, Vol. 21, Issue 10, pp. 11853-11861 (2013)

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A curvature fiber optic sensor using a two-core fiber (TCF) is proposed and demonstrated. The TCF is designed to operate as a directional coupler with one core located exactly at the center of the fiber and the other off-axis, but close to the center of the fiber. This design allows straightforward splicing of the TCF to single mode fibers (SMF), and alignment of the off-axis core is not strictly required for optimum operation. The sensor is fabricated by simply splicing a 5 cm long section of TCF between two SMF sections, which provides a sinusoidal spectral response. When the fiber is bent, the coupling parameters are modified due to stress-optic and effective length effects, effectively blue-shifting the sinusoidal spectral response of the sensor and allowing for the measurement of curvature. The sensor exhibits linear response and a sensitivity of −137.87 nm/m−1 for curvature ranging from 0 to 0.27 m−1, making it suitable to measure small curvatures with high sensitivity.

© 2013 OSA

OCIS Codes
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(120.0280) Instrumentation, measurement, and metrology : Remote sensing and sensors
(280.4788) Remote sensing and sensors : Optical sensing and sensors

ToC Category:

Original Manuscript: March 7, 2013
Revised Manuscript: April 23, 2013
Manuscript Accepted: April 27, 2013
Published: May 8, 2013

J. R. Guzman-Sepulveda and D. A. May-Arrioja, "In-fiber directional coupler for high-sensitivity curvature measurement," Opt. Express 21, 11853-11861 (2013)

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