Theoretical and experimental analysis of a chromatic dispersion compensating module using a dual concentric core fiber

New designs of optical fibers are widely used in dispersion compensating module (DCM) inserted in optical links to improve the bit rate. Dual concentric core fibers (DCCFs) can exhibit a very large negative dispersion coefficient and a large figure of merit well suited for DCM applications. However, these fibers intrinsically propagate two supermodes. So a selective injection of the mode of the central elementary guide of DCCF can be realized by the input connection with a single-mode fiber to obtain a negative dispersion. In this paper, we demonstrate theoretically and confirm experimentally the impact of this particular injection. The complete association of a DCCF connected on each end with single-mode fibers, corresponding at a DCM, is studied. A new definition of the chromatic dispersion (CD) for a DCM based on the phase delay method is established. The corresponding curve presents two symmetric maxima and becomes null at the phase matching wavelength. Experimental verification is presented and the influence of the optogeometrical parameters on the evolution of the CD is also discussed.