Novel device for achieving negative or positive dispersion and its applications

A known way to implement sufficiently efficient dispersion is based on a long fiber (few kilometers). An alternative might be a configuration of grating pair that is more compact and adjustable. However, in such a configuration negative dispersion (negative β₂ coefficient. β₂ is defined in eq. 1) cannot be achieved easily. In addition a real time control of dispersion coefficients is almost impossible. The combination between a positive and a negative dispersion medium in cascade is necessary for obtaining a dispersion compensation of temporal signals. In this paper we suggest a novel device that may be constructed to obtain both negative or positive dispersion coefficient. The suggested system is based on the all diffractive achromatic Fourier transform setup. Using the suggested setup the amount of the negative or positive dispersion may be easily controlled.