In this paper, an all-fiber mode selective coupler based on vector modes is proposed, which consists of a single mode fiber and an air-core ring few mode fiber. Based on the mode-coupling theory, the coupling characteristics of this vector mode selective coupler are investigated. In addition, we explore the influences of core distance on the crosstalk between high order vector modes and the working bandwidth. The results show that this vector mode selective coupler can realize the coupling from the fundamental mode to the special high order mode with a high coupling efficiency in the wavelength range of 15431556 nm. The crosstalk and the working bandwidth can be regulated by changing the core distance. Moreover, the low crosstalk and the wide bandwidth mode coupling are achieved at a core distance of 11 μm. The results in this paper can find applications in fiber lasers, optical tweezers, and mode division multiplexing systems.
Yinghao Guo, Mei Liu, Min Tang, Wenhua Ren, Guobin Ren. All-Fiber Mode Selective Coupler Based on Vector Modes[J]. Chinese Journal of Lasers, 2022, 49(3): 0306004