A new technique for the measurement of the nonlinear refractive index in optical fibers

In the last years, acousto-optic (AO) interaction has been proved to be a powerful and highly sensitive method for fine characterization of optical fibers. The key of the technique relies on the high sensitivity of the AO phase-matching condition with the structural and material properties of the fiber, enabling the detection of sub-nanometer fiber radius variations, or core refractive index variations in the order of 10 −8 in single-mode fibers. In this contribution, we present our results on the use of in-fiber AO interaction for the measurement of the nonlinear refractive index in single-mode optical fibers.