  In this article we have theoretically investigated the dispersion
characteristics of dual-core PCF, based on square-lattice geometry by varying
different parameters. The fiber exhibits a very large negative dispersion
because of rapid slope change of the refractive indices at the coupling
wavelength between the inner core and outer core. The dependence of different
geometrical parameters namely hole-to-hole spacing (pitch) and different
air-hole diameter (d) was investigated in detail. By proper adjustment of the
available parameters, a high negative dispersion value of -47,500 ps/nm/km has
been achieved around the wavelength of 1550nm. Our proposed fiber will be an
excellent device for dispersion compensation in long-haul data transmission as
being thousand times more than the available DCFs.
