Graded‐Index Ytterbium‐Doped Optical Fiber Fabricated through Vapor Phase Chelate Delivery Technique

Abstract

Herein, the fabrication of ytterbium‐doped graded refractive‐index few‐mode fiber (GRIN‐FMF) is described for the first time following a vapor phase chelate delivery technique. Investigation is carried out to find out the best possible approach to fabricate the preform. The optimization of the process steps along with composition and associated process parameters leads to a parabolic refractive‐index profile with a profile parameter of 2 in the developed fiber. A large core of 30 μm diameter and a low numerical aperture (NA) of 0.08 with graded distribution of dopant ions is achieved with a good repeatability. Amplification gain of more than 20 dB with good beam quality for pulses with kW peak power without any distortion in temporal, spectral, and spatial profile proves the potential of the fiber for many promising applications.

Active Optical Fibers and Components for Fiber Lasers Emitting in the 2-μm Spectral Range

“…Lower electrostatic forces on the nanoparticles’ surface allows to increase the final dopant concentration and to also improve the spatial homogeneity of the fibers [ 44 , 45 , 46 ]. Despite the rapid development of advanced deposition methods, such as direct nanoparticle deposition [ 47 ], aerosol deposition [ 48 ], or chelate deposition [ 49 ], the ND method remained the favorable technology for its feasibility and cost effective technological equipment.…”

Novel Dopant Tailored Fibers Using Vapor Phase Chelate Delivery Technique

“…RE-doped GRIN fibers are hard to fabricate using the SD technique as it requires multiple solutions to manage the graded distribution of dopants. [20,21] Recently, Lipatov et al established multicomponent (Er 2 O 3 -Yb 2 O 3 -F-P 2 O 5 -SiO 2 ) glass fibers using VPCD, demonstrating low-numerical aperture (NA) and largemode area (LMA) fibers for high-power fiber lasers. [22] Although by this time, VPCD is an established fabrication technique for large core fiber, the development of a complex waveguide design is often desired for the fiber to be used at a high-power level.…”