Recent Advances in Chirally-Coupled Core Fibers

Abstract

To meet the needs of high-power fiber lasers, a new fiber structure called chirally coupled core (CCC) fiber has attracted the attention of researchers all over the world. CCC fiber consists of two cores, one of which is a central core distributed along the axial direction, and the other is a side core that is offset from the central axis and spirally distributed around the central core. Meanwhile, CCC fibers are helical-translation symmetric. The unique structure results in advantages of robust single-mode performance, mode-distortion-free splicing and compact coiling of CCC fiber. Based on a brief description of the theory about CCC fiber, this article focuses on the research progress and application prospect of CCC fiber.

Optimization and Demonstration of Direct LD Pumped High-Power Fiber Lasers to Balance SRS and TMI Effects

“…Considering the mode control in the fiber, the optimization of the fiber structure is carried out to suppress the higher-order modes, which is conducive to improving the TMI threshold. These special fiber designs include photonic band gap fiber, large pitch fiber (LPF), confine doped fiber, multi-core fiber, and so on [31][32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48]. In addition, fiber coiling is also an effective measure to improve the TMI threshold by suppressing higher-order modes [6,[49][50][51].…”

Impact of the central refractive index dip of fibers on high-power applications

“…This kind of fiber has been widely used in optical communication [3], sensing [4], as well as high-power lasers [5][6][7][8][9][10][11][12][13][14][15]. On the other hand, more complex RI profiles such as parabolic [16], pedestal [17], W-type [18], M-type [19,20], single trench [21], modified single trench [22], multi trench [23], Bragg [24], chirally-coupled core [25], and photonic crystal fibers [26] have also been developed for different applications.…”