Highly Dispersive Optical Fiber for Orbital Angular Momentum Modes

Orbital angular momentum (OAM) modes, featured by the unique properties of the helical phase front and annular intensity profile, have shown enormous potential for a wide range of applications. Optical fibers with ring-shape profile have been experimentally proven for supporting stable OAM beam propagation. In most instances, managing the chromatic dispersion is of vital importance in a variety of optical fiber systems. In this paper, we summarize optical fibers with concentric ring cores for extremely dispersive OAM modes. The properties of the OAM mode in double ring-core fiber are presented, including the effective refractive index, effective mode area, power integral ratio, chromatic dispersion, and loss. Photonic crystal fiber and triple ring-core fiber, which share the same operation principle for dispersive OAM modes as the one in the dual-ring fiber, are also briefly introduced.