3SAE's Ring of Fire® technology is the industry standard for fusion splicing and optical fiber glass processing.
Ring of Fire® is 3SAE's patented 3-electrode wide area plasma architecture for fusion splicing and optical fiber glass processing. Three electrodes driven by three-phase current form a triangular plasma that encircles the fiber, heating it uniformly from every side instead of streaming heat across it like a conventional 2-electrode arc. That circumferential symmetry lets one splicer process fibers larger than 1 millimeter in diameter, roughly twice the working range of a standard fusion splicer, and it produces a centrosymmetric refractive-index profile at the splice. The same heat source removes polyimide coatings, draws tapers, forms end caps and mode field adapters, and builds optical combiners across multi-core and hollow-core specialty fiber.
How 3-electrode Ring of Fire® Splicing Works
A standard fusion splicer fires plasma between two electrodes. The stream crosses the fiber from one side to the other, so even with perfect mechanical alignment the heat lands asymmetrically. Over the molten zone, asymmetric heat drives asymmetric dopant diffusion, and the result is a non-centrosymmetric index profile at the splice. The penalty is small on telecom fiber and grows quickly as fiber diameter increases.
3-electrode Ring of Fire® removes that asymmetry by design. The three-phase discharge surrounds the fiber, and the glass absorbs heat from the radiation of recombining plasma rather than from particle collision on one face. The thermal field is circumferentially uniform, the index profile stays symmetric, and modal content holds stable through repeated re-arcing, where a 2-electrode splice degrades.
What Ring of Fire® Technology Enables
Before Ring of Fire®, standard fusion splicers could not reliably handle fibers larger than 600 microns. The wide area plasma source lifts that ceiling past 1 millimeter, which opens the full range of specialty glass processing: large diameter and large-mode-area fiber splicing, fiber-based tapers, end caps, mode field adapters, and optical combiners, plus polyimide coating removal and work on multi-core and hollow-core fiber. The architecture ships across 3SAE’s glass processing product line and powers specialty fusion splicing for production environments that demand operator-independent repeatability across shifts and batches.
Independent Validation: The Scarnera Thesis
A 2020 doctoral thesis from the University of Southampton Optoelectronics Research Centre put 3-electrode Ring of Fire® and 2-electrode arc splicing head-to-head on the same fibers. Using refractive-index profilometry and S2 modal analysis at the splice, the study found the 3-electrode architecture produces a more symmetric index profile and holds modal content stable through repeated re-arcing, while the 2-electrode profile degrades. The work was sponsored by SPI Lasers, and the optimized splice it identified entered mass production on a 3-electrode FITEL platform.
Our executive technical brief summarizes the findings for engineers evaluating specialty splicing capital, with the cited thesis sections and the measured performance gap between the two architectures.
The full thesis is publicly available at DOI 10.5258/SOTON/D1215.
Products That Use Ring of Fire® Technology
The architecture validated by the Scarnera thesis is available today in 3SAE’s flagship splicing lineup. The FITEL S185 specialty fusion splicer combines a 3-electrode Ring of Fire® arc with the compact FITEL S185 platform and supports specialty fibers up to 800 micron cladding diameter, including polarization-maintaining, multi-core, and hollow-core fiber. Ring of Fire® Wide Area Plasma Technology™ is also available across the 3SAE glass processing product line.
3SAE Technical Paper
High-power, Fused Assemblies Enabled by Advances in Fiber-Processing Technologies (© 2011 SPIE)
The power handling capabilities of fiber lasers are limited by the technologies available to fabricate and assemble the key optical system components. Previous tools for the assembly, tapering, and fusion of fiber laser elements have had drawbacks with regard to temperature range, alignment capability, assembly flexibility and surface contamination. To provide expanded capabilities for fiber laser assembly, a wide-area electrical plasma heat source was used in conjunction with an optimized image analysis method and a flexible alignment system, integrated according to mechatronic principles
3SAE Technical Paper
Large Area Isothermic Plasma for Large Diameter and Specialty Fiber Splicing (© 2007 OSA)
A device is presented that creates a large area plasma for splicing optical fibers. The isothermic thermal properties of the plasma facilitate splicing fibers >1mm in diameter without sacrificing splicing performance of standard fibers
Frequently Asked Questions
What is Ring of Fire® technology?
Ring of Fire® is 3SAE’s patented 3-electrode wide area plasma source for fusion splicing and optical fiber glass processing. Three electrodes driven by three-phase current create a triangular plasma that surrounds the fiber and heats it uniformly, which lets a single splicer process fibers larger than 1 millimeter in diameter.
How is 3-electrode plasma splicing different from 2-electrode arc splicing?
A 2-electrode splicer streams plasma across the fiber and heats it from one side, producing an asymmetric index profile that worsens as fiber diameter grows. A 3-electrode Ring of Fire® source encircles the fiber, delivers heat symmetrically, and produces a centrosymmetric index profile that stays stable through repeated re-arcing.
What fiber sizes can Ring of Fire® process?
Ring of Fire® handles fibers larger than 1 millimeter in diameter, roughly twice the range of a standard 2-electrode fusion splicer. The FITEL S185EVROF supports specialty fibers up to 800 micron cladding diameter.
What applications use Ring of Fire® technology?
Large diameter and large-mode-area fiber splicing, fiber-based tapers, end caps, mode field adapters, optical combiners, polyimide coating removal, and work on multi-core and hollow-core specialty fiber.
Which 3SAE products use Ring of Fire® technology?
The technology ships across the 3SAE glass processing product line and in the FITEL S185 specialty fusion splicer through a technology partnership with 3SAE.
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