Power splitting and switching in a multi-core fiber based on the multimode interference effect.

Abstract

In this paper, we propose a novel 1 to N optical power splitter and a 1 to N optical switch for a multi-core fiber (MCF) with N circularly aligned cores. The splitter and the switch are based on the multimode interference (MMI) effect inside a ring core fiber. The MMI effect will convert one image into N output images in the ring and therefore, the ring shape MMI coupler can act as a 1 to N power splitter. These images will have different phases. If two ring shape MMI couplers are used and a tunable phase shifter array and a fixed phase shifter array are placed between them, by properly setting the phases of the N images in the middle of the MMI couplers, the images will converge to one output port of the 2nd MMI coupler. The output port number can be changed by tuning the phase shifters. In this way, the input signal at one of the cores of the MCF can be switched to the other core, and a 1 to N switch can be realized. In the analysis, it is found that only one control parameter is required for the phase adjustment of the tunable phase shifter array in order to achieve the switching between the cores.