Bending characteristic of large-mode-area fibers with uniaxial crystal material cladding

摘要

A large-mode-area (LMA) fiber with uniaxial crystal material cladding is proposed in this paper. The modified refractive index of the cladding is derived, and bend-induced characteristics of a fiber with cladding made of potassium dihydrogen phosphate (KDP) are numerically investigated using Finite Element Method (FEM). The simulation results indicate that effective mode area (A(eff)) of the KDP-cladding fiber with maximum core radius of 21 mu m is up to 785.58 mu m(2) that is 19 mu m(2) greater than that of conventional silica-based LMA fiber with maximum core radius of 22 mu m. Furthermore, single-mode length of this KDP-cladding fiber is 3m shorter than that of conventional silica-based fiber, and it is helpful for suppressing nonlinear effects. Results suggest that KDP-cladding fiber can effectively mitigate bend-induced mode area compression, maintain the high beam quality and reduced nonlinear effects. These excellent properties of the proposed LMA fibers are potential for developing a compact high power fiber laser and amplifier system.