Polarization-Maintaining Few-Mode Optical Fibers with Air-Hole Structures

Novel few-mode optical fibers create an exciting opportunity for achieving very high transmission capacity and channel density. By introducing air-holes and employing elliptical ring core shape, the degeneracy of a mode group can be splitted, leading to large separation between two adjacent modes. Based on this idea, we report two kinds of air-holes assisted elliptical ring core fibers, each of which can support 10 (or even more) distinct polarization-maintaining modes over a broad wavelength range of 1.51–1.63 µm. The proposed fibers might be promising candidates for mode-division multiplexing system.