Mode-dependent analysis of a fiber optic curvature sensor with sensitive zone

In this paper, mode-dependent analysis of fiber optic curvature sensor with precision machined structural imperfections (teeth) as sensitive zone is conducted. Using controlled input or light source launching conditions sensor response is measured for different modes excited in the multimode optical fiber. Study shows that as curvature changes there is significant difference in how sensitive zone affects low and high order modes propagating through the fiber. Obtained measurement results provide further insight into FOCS response and open possibilities for development of new measurement approaches which represent a significant step forward for FOCS based measurement systems. Guidelines for maximizing sensor sensitivity, increasing measurement reliability and even avoiding intensity based measurement by measuring changes in the width of the sensor’s output light intensity distribution are discussed in this work. [Display omitted] •Intensity based fiber optic curvature sensor with sensitive zone is analyzed in terms of mode-dependent attenuation.•New insight into how different modes, excited in the MM optical fiber, are affected by sensitive zone as curvature changes.•Guidelines for maximizing sensitivity, increasing reliability and avoiding intensity based measurement are given.