Fabrication and Performance of a Heterogeneous-Helical-Cladding Fiber

Large mode area (LMA) fibers are widely used in high power fiber lasers to solve the nonlinear problems. In this work, a Nd
³⁺
-doped phosphate glass LMA fiber with heterogeneous helical claddings (HHC) is fabricated successfully by rod in tube method for the first time. The performance of the preform glass was matched well and suitable for drawing the fiber, and the related fabrication method is helpful for other special structure fiber fabrication. The fiber performance such as loss and gain coefficients are both tested and compared respectively. The experiment results show that the loss coefficient
α
will increase with the decrease of
Λ
(helix pitch) or
r
(fiber core radius), furtherly, the net gain coefficient
g
will become larger with the increase of
r
or
Λ
. The experiment results are beneficial to the HHC fiber design furtherly. As the HHC fiber has an all-solid-state structure, it is easy to fabricate relatively and convenient for cutting, splicing, etc. Thus, the HHC fiber will have potential applications in the field of fiber lasers.