High birefringent Brillouin frequency shifts in a single-mode As₂Se₃-PMMA microtaper induced by a transverse load

We report high Brillouin frequency shifts of 0.08±0.02  MHz/N in a 60 cm As₂Se₃-Poly(methyl methacrylate) (As₂Se₃-PMMA) hybrid microtaper with 2 μm As₂Se₃ core and 100 μm PMMA cladding diameters under a transverse load. Through finite element analysis of stimulated Brillouin scattering under the influence of contact stress from the loading fixture, such shifts are in accordance with a numerical value of 0.06±0.01  MHz/N. Further numerical analysis shows that uncertainties in the Brillouin frequency shift are the result of birefringence that is 27 times stronger than what is found in standard silica fibers.