Brillouin Characterization of ZBLAN Fiber for Strain and Temperature Sensing

We investigate the strain and temperature dependence coefficients of the Brillouin frequency shift in a ZBLAN (ZrF
₄
-BaF
₂
-LaF
₃
-AlF
₃
-NaF) fiber. The coefficients are found to be −90.9 MHz/% and −1.58 MHz/K for strain and temperature, respectively. These values are approximately −0.18 and −1.6 times those observed in silica fibers. Notably, the strain sensitivity of the ZBLAN fiber is the lowest recorded, to the best of our knowledge, when compared to other commonly utilized optical fibers, including polymer optical fibers. We further demonstrate distributed strain and temperature measurements along a 3-m-long ZBLAN fiber, showing its potential for applications in high-accuracy temperature sensing particularly with its minimal sensitivity to strain in comparison with other fiber materials.