Dynamic index modulation mechanism in polarization-maintained fiber Bragg gratings induced by transverse acoustic waves

A novel index modulation mechanism of polarization-maintained fiber Bragg gratings based on the mi- crobend of stress members induced by a transverse acoustic wave is proposed and investigated experimentally. The index modulation leads to a series of ghost gratings with specific polarization, whose wavelengths can be tuned by the acoustic wave frequency and whose intensities depend on the vibration direction of the transverse acoustic wave. Our method provides a novel way to achieve polarization- dependent narrowband acousto-optic tunable filters.