High resolution interferometric temperature compensation using optical fibers with different temperature coefficients

In this paper, we proposed the temperature compensation theory using a pair of unbalanced interferometers composed of different temperature coefficients' optical fibers. The difference between the temperature sensitivities of the two interferometers was analyzed in detail. The larger the difference of temperature coefficients of the sensing arms is, the longer the sensing arm is, and the higher the phase demodulation resolution is, the higher the temperature resolution is. The bend-insensitive single- mode fiber and Boron/Germanium co-doped fiber were used to develop two kinds of unbalanced Michelson interferometers for the experiment. The result showed a temperature sensitivity difference of 3.93 rad/degrees C and a temperature resolution of better than the order of 10-3 degrees C, which is suitable for achieving strain measurement of sub-n epsilon for crustal deformation measurement.