Abstract

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 has been demonstrated over the last decades using either flexural, longitudinal, or torsional elastic modes [1, 2]. From the practical point of view, the main limitation of such devices arises from the huge elastic attenuation in fibers with protective polymer coating. Consequently, the polymer jacket of the fiber section along which the acousto-optic interaction takes place must be removed. The bare fiber section compromises the long-term reliability of the component. Recently, acousto-optic coupling using torsional wave was demonstrated in thin metal-coated optical fibers [3]. The metal coating provides low attenuation of the elastic wave and surface protection of the fiber, but still fiber handling is compromised. In this paper, we present the first experimental demonstration of in-fiber acousto-optic coupling in polyimide-coated optical fibers.

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