Mode characteristics of few-mode optical fibers with assistant cores.

The mode characteristics of few-mode step-index optical fibers composed of a center core and a few assistant cores are investigated. Each fourfold mode in the optical fiber can be split into two twofold modes, avoiding strong mode coupling during the transmission process. In addition, two-mode operation in the fiber with a wide wavelength range of 1.42 to 1.9 μm is demonstrated numerically. We also investigated the coupling characteristics of the two-core configuration that can effectively separate the LP01 and LP11 modes. [ABSTRACT FROM AUTHOR]