Observation on temperature and strain dependency of Brillouin dynamic grating in a few-mode fiber with a ring-cavity configuration.

We experimentally conduct Brillouin dynamic grating (BDG) operation using a 1-km-long four-mode fiber. By employing a simplified ring-cavity configuration with single-end pumping, the BDG is effectively generated in $ {{\rm LP}_{01}} $LP01 mode within a range of 250 m, and three higher-order modes, namely, $ {{\rm LP}_{11b}} $LP11b, $ {{\rm LP}_{21a}} $LP21a, and $ {{\rm LP}_{02}} $LP02, are chosen as probes to analyze the BDG with a spatial resolution of 1 m. To the best of our knowledge, this is the first time to characterize the responses of BDG frequency to temperature and strain for different modes in a conventional few-mode fiber. By employing the pump-probe pair of $ {{\rm LP}_{01}}{{\rm - LP}_{02}} $LP01-LP02 mode, the highest temperature and strain sensitivities of 3.21 MHz/°C and $ - 0.0384\;{\rm MHz}/{\unicode{x00B5}}{\unicode{x03B5}} $-0.0384MHz/µÎµ have been achieved. Also, the performance of simultaneously distributed temperature and strain sensing based on BDG is evaluated.

Mode-selective few-mode Brillouin fiber lasers based on intramodal and intermodal SBS.

Mode-selective fiber lasers have advantages in a number of applications. Here we propose and experimentally demonstrate a transverse mode-selective few-mode Brillouin fiber laser using the mode-selective photonic lantern. We generated the lowest three orders of linearly polarized (LP) modes based on both intramodal and intermodal stimulated Brillouin scattering (SBS). Their slope efficiencies, optical spectra, mode profiles, and linewidths were measured.