Measurement of the nonlinear refractive index in optical fibers by acousto-optic interaction

Abstract

It is known that an acoustic/elastic wave propagating along an optical fiber has the capability to produce coupling between optical fiber modes. A variety of all-fiber, dynamic, and reconfigurable components based on this effect has been demonstrated over the last decades [1]. In the last years, acousto-optic (AO) interaction has been proved to be a powerful and highly sensitive method for the characterization of optical fibers [2, 3]. The key of the technique relies on the large sensitivity of the AO phase-matching condition with the structural and material properties of the fiber, being able 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 paper, we present our preliminary results on the use of in-fiber AO interaction for the measurement of the nonlinear refractive index in single-mode optical fibers.