Optical-fiber-attenuation investigation using stimulated Brillouin scattering between a pulse and a continuous wave

A new technique for measuring optical-fiber-attenuation characteristics is described. The technique uses stimulated Brillouin scattering in the fiber between a counterpropagating pulsed pump wave and a cw Stokes probe wave. Fiber attenuation is estimated nondestructively from amplification of the probe wave through stimulated Brillouin scattering. Experiments with a 5.2-km-long single-mode fiber reveal that the output signal is approximately 100 times that of the Rayleigh backscattered signal observed in conventional optical time-domain reflectometry. The signal fluctuation due to polarization-dependent Brillouin gain is successfully removed by polarization averaging.