Tunable multi-channel dispersion equalizer using a super-imposed fiber Bragg grating

We propose a new technique realizing a tunable multi-channel dispersion equalizer with the super-imposed fiber Bragg grating. Our simple method for linear chirp control is based on the strain gradient technique by sticking the FBG to the cone (or tube) of a changing circular curvature. This method allows us to control chirp and center wavelength of a broadband chirped grating. The dispersion characteristics can be tuned by applying displacement on the cone or changing the curvature of the tube. This method will be appropriate for future dispersion control in optical transmission systems, and can also be used as an optical filter with very large pass band or rejection band.