Two-Dimensional Finite-Element Modal Analysis of Brillouin Gain Spectra in Optical Fibers

A modal analysis based on two-dimensional (2-D) finite-element method for the Brillouin gain spectra (BGS) in optical fibers is demonstrated. This method enables the evaluation of optical fibers with 2-D complicated geometry and/or refractive-index profile. The BGS of two fiber samples, a single-mode fiber and a PANDA polarization-maintaining fiber (PMF) of the same design except the stress-applying elements in the PMF, are calculated using this analysis and compared to each other. The BGS are also tested experimentally for confirmation