Comparative analysis of stimulated Brillouin scattering at 2-µm in various infrared glass-based optical fibers

We provide experimental characterization of stimulated Brillouin scattering at 2-µm wavelength in step-index optical fibers made of various types of infrared materials. Our results show that the main characteristics of the Brillouin process such as the frequency shift, spectral linewidth, and gain can be widely tuned through the index-controlled guiding of both acoustic and optical waves as well as the intrinsic material properties of the fiber under test. More precisely, we found that depending on the used material the Brillouin frequency shift can be decreased by 30% in a common step-index fiber design, while its linewidth and gain efficiency can be increased by a factor 5 and 180, respectively, when compared with the standard silica fiber. Four families of fiber materials were analyzed near 2 µm as well as at 1.55 µm for comparison—namely, germanosilicate, zirconium fluoride, tellurium oxide, and sulfur-based chalcogenide. Our findings open the way for further fundamental investigations of stimulated Brillouin scattering and the development of practical applications in the 2-µm spectral range.