Cost-efficient frequency-domain scheme for forward stimulated Brillouin scattering measurements

We present a cost-efficient frequency-domain scheme for forward stimulated Brillouin scattering (FSBS) measurements in optical fibers. The proposed scheme relies on a single laser to excite and probe the transverse acoustic resonances of the fiber under test. A double sideband (DSB) modulated pump light is injected into the fiber, while the transmitted light is demodulated through a vector network analyzer after filtering out its upper (or lower) sidebands. Our experiments are corroborated by numerical simulations performed by solving the coupled equations taking both FSBS and Kerr effects into account. As a proof of concept, we tested our system with two fibers: a highly nonlinear fiber with acrylate coating for temperature characterization, and a bare standard single-mode fiber for mechanical impedance detection.