PRESSURE DEPENDENCIES OF RELATIVE CHANGE IN ELECTRICAL RESISTANCE, GAGE FACTOR AND POISSON'S RATIO IN BARE OPTICAL FIBERS

In this paper, a distributed sensing method relying on the principle of pressure dependencies of relative change in electrical resistance, gage factor and Poisson's ratio of the bare optical fiber core has been proposed. Using this method, besides the pressure information, relations between pressure and relative change in electrical resistance, gage factor and Poisson's ratio of the bare optical fiber core have been examined and then the temperature dependencies of these parameters have been mathematically analyzed and matching simulations have also been carried out in Matlab R2021b and Simulink environments. Moreover, first-order equations expressing the relations between these parameters and their temperature dependencies have been derived benefiting from the curve-fitting method. For pressure variations in the range of 2.2 x 10(7) Pa - 12 x 10(7) Pa, relative changes in electrical resistance of the fiber core have been obtained in the range of 0.41 x 10(-3) - 2.13 x 10(-3) . In other words, the pressure dependence of relative change in electrical resistance of the fiber core can be expressed as 1.841 x 10(-2)R(rc)(GPa)(-1) , i.e. 1 GPa pressure variation occurring along the fiber core causes about 0.01841 unit of Rrc variation. Furthermore, pressure dependencies of the gage factor and Poisson's ratio have been acquired as 2.924 x 10(-2) GF(GPa)(-1) and 1.462 x 10(-2) sigma(GPa)(-1) , respectively.