Compact fiber-optic vector inclinometer
What we believe to be a novel fiber-optical inclinometer based on a dual-path core-to-cladding mode coupling mechanism is demonstrated. Both the amplitude and tilt direction of bends about a 2-mm-long flexure joint in an optical fiber can be determined. The sensor head consists of a nonadiabatic abrupt taper cascaded with a weakly tilted fiber Bragg grating. Measured bend angles of up to 12° are demonstrated, as well as a method to increase the sensitivity for bend angles smaller than 4°.
Shao, L.-Y, & Albert, J. (2010). Compact fiber-optic vector inclinometer. Optics Letters, 35(7), 1034–1036.