Hole core fiber marks a turning level in fiber know-how. However first, there are obstacles to beat
In Sept, 2025, Microsoft Azure introduced it’s scaling its hole core fiber (HCF) manufacturing by outsourcing manufacturing to Corning and Heraeus. It made clear that the tech big is kind of critical about its dedication to high-capacity fiber innovation, regardless of its deep concentrate on AI — or particularly due to it.
Microsoft’s HCF play
In case you adopted the developments within the nascent HCF area, you’d know that Microsoft has been noodling with HCF R&D for fairly a while now.
At Ignite 2024, CEO Satya Nandella said that the know-how delivers “absolute breakthroughs” by way of pace, bandwidth, and energy effectivity in comparison with typical fibers.
The frenzy round hole core fiber isn’t just advertising and marketing fluff. Physicists on the College of Southampton in U.Okay. have proven that HCF reveals 35% much less attenuation and 45% quicker sign transmission in comparison with commonplace glass fibers.
The Azure group, testing Microsoft’s HCF answer over 1,200 Km of fiber final 12 months, achieved 0.091 dB per kilometer of transmission loss, the bottom ever recorded — and a far cry from the 0.14 dB/km of fiber networks.
“This low fiber loss is totally crucial for knowledge middle to knowledge middle connectivity, and we now have manufacturing routes of hole fiber operating. In reality, we’re going so as to add 15,000 further kilometers deliberate over the subsequent 24 months,” Nandella stated.
The deliberate 15,000 km of HCF route will lay the groundwork to deploy “end-to-end” HCF answer throughout Azure’s world community and obtain higher speeds and decrease latency to feed the hungry cloud and AI workloads in knowledge facilities.
Breaking a 40 12 months impasse
Optical fiber cables carry Web all over the world. They’ve a stable glass core that guides mild alerts by way of with the assistance of the core’s excessive refractive index. Hole core fiber takes it to the subsequent stage by swapping out the stable glass core with an air-filled one nested inside partitions created from ultra-thin glass membranes. As air is extra clear, photons journey quicker by way of this hole middle, whereas the encompassing glass membranes maintain the alerts transferring by way of with out scattering. This quantities of quicker transfers — and extra importantly, very low knowledge loss which is crucial for AI and high-performance computing (HPC).
This permits fiber gamers to sidestep an issue that has existed for 4 many years, sign loss and attenuation resulting in efficiency plateau in optical fibers. Even one of the best fibers out there want amplification each 12 kms or so.
The excessive transmission and decreased lack of HCF can show transformative for next-generation purposes like AI and distant knowledge facilities. Nevertheless, the efficiency acquire can considerably increase many different applied sciences as nicely, together with 5G/6G networks, quantum computing, protection communications, IoT sensible cities, and high-frequency buying and selling.
Challenges and limitations
Scala Knowledge Facilities, Lightera, and Nokia tag-teamed in November to conduct an HCF check in Sao Paulo. With optical testing and certification tools from Viavi, the trio examined AccuCore HCF, Lightera’s hole core fiber optic cable answer, demonstrating 32% discount in latency. The info transmission speeds are near “the pace of sunshine”, the businesses claimed.
“A 32% discount in latency time, verified utilizing commercially obtainable 400G excessive finish measurement tools corresponding to these from Viavi options, provides important weight to this check,” stated Andre Champavere, fiber optic measurement and sensing knowledgeable, in a LinkedIn remark. As for the OTDR [Optical Time Domain Reflectometer] characterization of HCF fibers, it’s considerably particular (very low backscatter stage, excessive reflective peaks at SMF/HCF hybrid connections), however it might work.”
However earlier than HCF turns into a medium of long-haul connectivity, an impediment course of challenges lay forward for HCF gamers. HCF cables have delicate microstructures which make dealing with and splicing a nightmare. The skinny partitions of the cables are liable to collapse, and consequently, delicate to bending. It calls for tight thermal management, sub-micron alignment, and exact humidity administration for manufacturing, set up and splicing
So, when an HCF cable breaks within the discipline, repairing turns into simply as tough. For one, there’s a restricted window by which the fibers should be spliced again collectively.
“You can’t go away it open for weeks or months,” Mario Simard, product line supervisor at Viavi stated in a webinar. “If there’s strain differential, you may get some contaminant contained in the fiber,” he added.
At present, the stable core and hole core infrastructures aren’t immediately suitable. “You must have an adapter from glass to air to attach the HCF to a system or to a check instrument,” Simard famous. Even so, adapter loss can result in a poor-quality hyperlink.
As with all new know-how, HCF too faces an absence of standardized Technique of Process (MoP) and absence of expert professionals which additional complicates check and monitoring.
The situation calls for specialised testing strategies and parameters, together with non-standard (OTDR) settings, further check wavelengths, and new post-processing evaluation algorithms. Finest practices, like testing the attenuation profile and chromatic dispersion are additionally crucial to keep away from surprises within the discipline.
Hole core fiber continues to be in its early phases, however one factor is obvious: hyperscalers and web service suppliers (ISPs) are taking curiosity and steadily deploying it in choose elements of the community to reinforce efficiency the place there may be demand. Facet by aspect, check suppliers are additionally engaged on the challenges behind the scenes, in order that when HCF turns into pervasive, firms have a loaded arsenal of check tools and trade requirements to leverage. Regardless that that’s nonetheless a number of years away, testing distributors are falling again on their many years of fiber testing experience to engineer new testing options that may make HCF a business actuality sooner or later.
