Compact omnidirectional multicore fiber-based vector bending sensor

We propose and demonstrate a compact and simple vector bending sensor capable of distinguishing any direction and amplitude with high accuracy. The sensor consists of a short segment of asymmetric multicore fiber (MCF) fusion spliced to a standard single mode fiber. The reflection spectrum of such a structure shifts and shrinks in specific manners depending on the direction in which the MCF is bent. By monitoring simultaneously wavelength shift and light power variations, the amplitude and bend direction of the MCF can be unmistakably measured in any orientation, from 0 degrees to 360 degrees. The bending sensor proposed here is highly sensitive even for small bending angles (below 1 degrees). This work was funded in part by the Fondo Europeo de Desarrollo Regional (FEDER), in part by the Ministerio de Ciencia, Innovacion y Universidades-under projects RTC2019-007194-4, RTI2018-0944669-B-C31 and PGC2018-101997-B-and in part by the Gobierno Vasco/Eusko Jaurlaritza IT933-16, ELKARTEK KK-2019/00101 (mu 4Indust), and ELKARTEK KK-2019/00051 (SMARTRESNAK). The work of Josu Amorebieta is funded by a PhD fellowship from the University of the Basque Country UPV/EHU