Micro-displacement measurement using a long period fiber grating in a self-referenced fiber optic intensity sensor

This work describes a sensor, in which the sensing head comprises a long period fiber grating (LPG) whose attenuation peak varies as function of its bending. The level of LPG bending is induced by the displacement of a micrometer translation stage (MTS) being possible therefore to measure microdisplacements. The sensing head is integrated in a fiber optic intensity sensor, referenced in frequency, which is immune to intensity fluctuations other than the ones caused by the LPG.