High sensitivity curvature sensor with a cascaded fiber interferometer

This paper presents a cascaded fiber interferometer sensor, which is fabricated by fusion splicing of single-mode fibers. The coupling and interference for the CFI were mathematically and experimentally studied. An equal model has been built for the CFI. Furthermore, the curvature sensitivity were explored in sensor application. The curvature sensitivity for the cascaded fiber interferometer is very high, which can achieve 790.18 pm/m −1 . Besides, the proposed sensor has advantages like good repeatability, low cost, and simple structure.