, Volume 3, Issue 1, pp 52-56,
Open Access This content is freely available online to anyone, anywhere at any time.
Date: 31 Aug 2012

Temperature-independent torsion sensor based on “figure-of-eight” fiber loop mirror


An interrogation sensor system combining the “figure-of-eight” fiber loop mirror using a single directional 3×3 fiber optic coupler was proposed. One fiber loop mirror was formed by inserting a length of high birefringent optical fiber at the input ports of the 3×3 coupler. Splicing the output ports of the 3×3 coupler between them created the other fiber loop mirror. The introduction of this second loop gave rise to two polarization states of light with the same frequency but different optical phase. The mechanical torsion sensing head was located at the second loop and was exhibited an average modulus torsion sensitivity of 7.9×10−4 degree/dB. The performance of the sensor was not affected by environmental temperature variations.

This article is published with open access at Springerlink.com