We demonstrate an up to 1200°C high-temperature distributed Brillouin sensing based on a pure-silica photonics crystal
fiber. A Brillouin frequency shift (BFS) hopping is observed between 800°C-900°C for the first annealing process and
after that the BFS exhibits the stability and repeatability with a measurement accuracy as high as ±2 °C . The BFS
dependence on temperature in the range of room temperature to 1200°C agrees well with an exponential function instead
of a linear function, which is mainly attributed by the change of the acoustic velocity in a silica fiber.
We report on a high-sensitive distributed transverse load sensing based on Brillouin dynamic gratings (BDGs) for the first time to the best of our knowledge. The sensing mechanism is to measure the transverse-load induced birefringence through exciting and probing a BDG in an elliptical-core polarization-maintaining fiber. A distributed measurement of transverse load is experimentally demonstrated with a 20-cm spatial resolution, and the measurement accuracy is as high as 4.8x10<sup>-4</sup>N/mm, which improves by three orders of magnitude compared with the prior techniques.
In this paper, a novel method for an ultrahigh resolution optical spectrometry based on Brillouin dynamic gratings (BDGs) is proposed and demonstrated. A coherent acoustic wave is generated in an optical fiber through stimulated Brillouin scattering, and the acoustic wave modulated the fiber refractive index forming a BDG. An ultra-narrow bandwidth optical filter is constructed by operating a BDG in a long single-mode fiber (SMF), and the optical spectrometry is performed by sweeping the center wavelength of the BDG-based filter through a swept-tuned laser. In the experiment, a 4-fm (0.5 MHz) spectral resolution is achieved by operating a BDG in a 400-m SMF.