Group delay control of super-imposed fiber gratings using a two-column system mounted on a rotatable disk

A novel method for dispersion control of a fiber grating is proposed and experimentally demonstrated. A super-imposed fiber Bragg grating (SFBG) is attached on an elastic plate and wound around two columns, which are rotated on a disk. The system induces strain gradient for chirping that can be controlled by the rotation of the disk. The central reflection wavelength can be either maintained or changed by controlling the position of the grating with respect to the two columns. Various group delay curves can be obtained by altering the shape of the plate on which the SFBG is attached. In addition, the proposed device can also be used as a broad-band tunable filter in optical communication systems.