Dynamic behaviors of optical vortices in dual-core photonic crystal fibers

Novel evolution dynamics of optical vortices propagating in a dual-core photonic crystal fiber (PCF) is investigated, which can be explained well by using the equivalent dipole mode superposition principle. Thanks to the coupling between the two cores of PCF, exciting vorticity splitting and topological charge-flipping are achieved by inducing a vortex beam into one of the two cores of the PCF. What is more, the evolutions of two vortices located in each core separately can be controlled by means of modulating the initial phase difference of them. Our results may offer possibilities for applications of optical vortices, orbital angular momentum modulations, as well as optical communications.