Measurement Setups and Protocols

This chapter describes the experimental setups and measurement protocols used in the characterization of forward Brillouin scattering processes in optical fibers. The methods can be broadly classified in three categories: techniques in which forward Brillouin scattering is accumulated and integrated over the entire length of a fiber under test, point measurements at specific locations, and spatially distributed analysis of the scattering spectra as functions of position. Specific examples include the spontaneous scattering of probe waves within fiber interferometer loops, polarization rotation of probe waves, photoelastic perturbations of fiber Bragg gratings, coupling of power between forward Brillouin pump tones, and spatially distributed mapping of auxiliary backscattering processes such as Rayleigh or backward Brillouin. Lastly, the spatially distributed analysis of inter-modal scattering over polarization-maintaining fibers is discussed.