Determination of Brillouin backscattering strain and temperature coefficients in telecommunication optical fibers

Abstract—In this paper, the Brillouin spectra of silica-based optical fibers were investigated, and their temperature and strain dependence were determined. The values of the thermal coefficients are more diverse than those of the strain, based on the twelve commercially available optical fibers. The values ranging from 1.1 to 1.4 MHz/°C and from 0.043 to 0.053 MHz/με for the thermal and strain coefficients, respectively. Furthermore, the temperature influence on Brillouin frequency shift was measured for tight buffer and loose tube type cables. Long-term measurements of the outside ambient temperature were carried out to determine the absolute error in comparison to thermocouple.