Abstract

Brillouin-gain-spectrum measurement along an optical fiber has recently gained a lot of interest owing to its potential for strain monitoring in installed cables¹ and for distributed temperature sensing.² This measurement requires two lightwaves propagating in opposite directions through the fiber. One pumps the medium, and the other acts as probe signal and thus experiences amplification when it lies within the Brillouin-gain spectral range (12-13 GHz below the pump-light frequency near 1300 nm). Most of the methods reported to date use either two distinct laser sources,^1,2 causing problems when the fiber ends are remote, or a single laser source, at the expense of setup complexity.³

© 1994 Optical Society of America