Optical Fiber Fabrication Using Novel Gas-Phase Deposition Technique

Abstract

Abstract-We report a highly versatile chemical-in-crucible preform fabrication technique suitable for gas-phase deposition of doped optical fibers. Aluminosilicate and ytterbium-doped phosphosilicate fibers are presented demonstrating the technique and its potential for realizing complex fiber designs which are suitable for the nextgeneration of high power fiber devices. The results show aluminum doped fiber with NA of 0.28 and ytterbium-doped fiber with a measured slope efficiency of 84 % with respect to pump launch power.

An Optimized Vapor Phase Doping Process to Fabricate Large Core Yb-Doped Fibers

“…The dopant concentrations at the two ends of the preform have been presented in Table III. The background loss of the fiber is ∼21 dB/km at 1200 nm, which is comparatively much lower than the previous reported results of Yb-doped fibers [17], [22], considering the Yb 2 O 3 concentration >0.4 mol%. The OHabsorption centered at 1380 nm indicates ∼2.3 ppm of water in the fiber which is notably lower than the reported results [11], [18].…”

“…As described in the earlier reported results, this process suffers from poor repeatability [12], [22], "clogged" delivery lines due to condensation of precursor materials [22], [23], shorter usable preform length [13], [14], lower RE concentrations [12], [13], non-uniform RE distribution along the length of the preform [15] and higher OH − content in the fibers [11], [18]. So, the prime target of this study was to demonstrate a standardized process technology to fabricate LC, low numerical aperture (NA) and high Yb-doped fibers for laser applications with higher reproducibility.…”

“…However, till date, very few fibers are made by this method [11]- [18] due to many critical challenges of the process, viz. decomposition of RE compounds prior to the reaction zone, blocking of delivery lines due to condensation of precursor materials [22], [23], variation in dopants concentration over the length of the preforms [15], [22] etc. This paper reports a systematic investigation on process parameters of vapor phase doping technique for fabrication of highly Yb-doped optical fibers in reliable manner.…”

Vapor Phase Doping of Rare-Earth in Optical Fibers for High Power Laser

“…However, till date, a limited number of successful fabrications of active fibers have been reported by using this technique [10][11][12][13]. The prime challenge related to the process technology was to implement the external delivery system proficiently [14] due to the following difficulties: condensation of precursor materials during transportation, blocking of the dopant delivery lines, decomposition of RE compounds prior to the reaction zone, variation in dopant concentrations over the length of the preform. Thus the process suffers from poor repeatability [10], shorter preform length [11,12], lower concentration of RE 2 O 3 [10,11] and higher OH − content in the fibers [8].…”

Yb-doped LMA Fiber Fabricated by Chelate Deposition System for High Power Laser Applications

“…Optical fibers fabricated for high power laser or amplifier applications require the core to be doped with active rare earth (RE) ions like ytterbiu m (Yb ). Rare-earth doped optical fibers based on fused silica glass are common ly produced using modified chemical vapor deposition (MCVD) technique with a certain doping system, such as solution doping and vapor doping techniques [2][3][4][5]. Solution doping technique (SDT) is a tradit ional well-known method for many years, but was found to limit RE concentration, induced RIP v ibration, ion clustering and other shortcomings, which limits its applicat ion in h igh power fiber laser development.…”