Bend and stretch sensor based on singlemode-multimode-singlemode fiber optic structure

The possibility of measuring the bending deformation of a metal beam using a fiber-optic structure consisting of a piece of 62.5/125 𝜇m multimode fiber with a length of 8.8 mm welded between standard single-mode fibers (Singlemode-Multimode-Singlemode, SMS structure) was investigated. It is shown that when an SMS structure is attached to a bending metal beam, the dependences of the transmitted power on the bending, curvature and stretching of the beam are linear, which reflects the prospects for using SMS structures as a simpler and more economical alternative to sensors based on fiber Bragg gratings.