Investigation of a novel temperature-sensing mechanism based on strain-inducedoptical path-length difference in a multicore optical ber

Abstract

A four-core optical ber is employed to investigate a novel temperature-sensing mechanism, which is basedon the strain-induced optical path-length difference between the ber core pairs. A short segment of a four-core ber iswound around a solid stainless steel cylinder to form a tight circular loop, which is exposed to temperatures of up to 100◦C. Temperature-induced radial expansion of the stainless steel cylinder causes a shear strain in the ber and introducesan optical path-length difference between the ber core pairs. This results in a total phase shift of about 20.40 0.29rad in the interference pattern of the four-core ber, which is monitored by a CMOS camera. The temperature-inducedphase and strain sensitivities are measured to be 3.74 rad/m◦C and 0.18 \"/◦C, respectively