Multimode interferometer-based torsion sensor employing perfluorinated polymer optical fiber

This paper reports a torsion sensor based on the multimode interference theory. The sensor is fabricated by sandwiching a section of perfluorinated polymer optical fiber (POF) between two silica single mode fibers to construct a single-mode-multimode-single-mode (SMS) structure. The perfluorinated POF is easily connected to the optical fiber via the precise alignment of ceramic ferrules and ceramic mating sleeve. With the considerable flexibility and deformability of the perfluorinated POF, the proposed sensor is especially suitable for torsion measurement. Experimental results show that a wavelength sensitivity of 106.762 pm/(rad/m) and an intensity sensitivity of 0.165 dBm/(rad/m) are obtained within a large torsion rate of −100∼100 rad/m.