Tunable optical delays based on Brillouin dynamic grating in a polarization maintaining fiber

We demonstrate a novel kind of tunable optical delays based on dynamic grating generated by Brillouin scattering in an optical fiber. An axial strain gradient is applied to a 15 m section of a polarization-maintaining fiber, and the Brillouin reflection grating is generated positionselectively by controlling the optical frequencies of Brillouin pump waves. Tunable time delays of up to 132 ns are achieved with an 82 ns Gaussian pulse.