Potential Applicability of Brillouin Scattering in Partially Chlorinated Polymer Optical Fibers to High-Precision Temperature Sensing

Using the ultrasonic pulse-echo technique, we estimate the Brillouin frequency shift (BFS) and its temperature dependence in partially chlorinated graded-index polymer optical fibers (PCGI-POFs), which have high thermal stability compared with other POFs. At 1550 nm, the estimated BFS is ?4.43 GHz with its temperature coefficient of approximately -6.9 MHz/K, which is ?5.8 times as large as that in silica fibers. Since the fracture strain is ?3.0% (mostly in the elastic region), the BFS dependence on strain in PCGI-POFs cannot be estimated by this technique. These results indicate that Brillouin scattering in PCGI-POFs has a big potential for distributed high-precision temperature sensing.