[HN Gopher] Hollow Core Fiber (HCF)
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Hollow Core Fiber (HCF)
Author : giuliomagnifico
Score : 51 points
Date : 2025-05-09 13:25 UTC (9 hours ago)
(HTM) web link (www.holightoptic.com)
(TXT) w3m dump (www.holightoptic.com)
| epx wrote:
| Curious about how difficult would be to splice it.
| giuliomagnifico wrote:
| Good point. I have no idea, but probably the tools will need an
| upgrade!
| josephthejoe wrote:
| yea hand splicing in the field is already super rare today. I
| imagine this cannot be hand spliced at all.
| burnte wrote:
| Considering the number of fiber splice trucks rolling around
| I think your supposition is incorrect. Fiber splicing happens
| thousands of times every day. Fibers break and get cut all
| the time. Tt's not common in data centers, but once you leave
| those walls fiber splicing happens everywhere every day.
| 0_____0 wrote:
| I've personally spliced about a dozen optical fibers and I
| don't even work in telecom :)
|
| Not exactly by hand though - all the prep is done by hand but
| the actual alignment and fusion steps were automated by the
| fusion splicer machine (about the size of a small toolbox)
| richardwhiuk wrote:
| https://techcommunity.microsoft.com/blog/azurenetworkingblog...
|
| Suggests it can be to some extent.
| sunrunner wrote:
| Not a comment on the article, but the linked URL makes me vaguely
| uncomfortable.
| crunchbang-excl wrote:
| That fullwidth question mark really makes the URL stand out,
| not in a good way.
| escape_goat wrote:
| I think that it was good that it stood out to be honest.
| formerly_proven wrote:
| Slightly too clever CMS. Like Dolphin replacing slashes with
| the Unicode fraction slash.
| ksec wrote:
| Hollow-core optical fibers may have a bright future [1], along
| with another HN thread from 8 years ago [2], I have longed for
| these cables where we could cut Japan to New York latency by
| 50ms.
|
| Unfortunately we dont seems to be anywhere close to it.
|
| [1] https://www.laserfocusworld.com/fiber-
| optics/article/1417001...
|
| [2] https://news.ycombinator.com/item?id=16194973
| giuliomagnifico wrote:
| No... hollow core fibers are being installed as a test in some
| data centers now/this year. Who knows how many years it will
| take to (re)make an oceanic backbone (and the prices...)
| RationPhantoms wrote:
| I'd also argue that the 50ms reduction time benefit with HCF
| has waned with the introduction of HFT (High Frequency
| Trading) over LEO links with lasers.
| GlibMonkeyDeath wrote:
| I was going to do the "well akshually..." about HCFs because this
| article is so light on details. I used to work in a related field
| many years ago, and the attenuation of these fibers relegated
| them to niche applications (short-lengths that needed the odd
| properties of a hollow core, like ultra-high power transmission,
| low dispersion, low nonlinearity, etc.) They were orders of
| magnitude too lossy for long-haul telecommunications applications
| at the time.
|
| But a quick search proved my knowledge was not up to date - here
| is the paper linked from the Laser Focus World blurb someone
| linked above. Looks like HCFs have achieved loss parity with
| traditional single-mode fused silica fibers, at least in the lab.
| Pretty amazing and cool if you ask me!
|
| https://eprints.soton.ac.uk/470034/1/OFC2022_PD_Jasion_submi...
| pletnes wrote:
| Do the wave modes offer higher velocity?
| GlibMonkeyDeath wrote:
| Yes, basically most of the electromagnetic wave is in the
| hollow (gas-filled) core, which is going to have an index
| closer to 1 (as opposed to ~1.4 for silica fibers.)
| chorsestudios wrote:
| A key detail I found lacking in this article was the
| manufacturing cost difference. It mentions that it is more
| expensive, but no indication of how much more expensive.
| GlibMonkeyDeath wrote:
| A lot more expensive right now. But silica fiber
| manufacturing has been optimized like crazy for 50 years, so
| that's not a surprise.
|
| From a high level, the preforms are a lot more complicated,
| and I imagine the draw process might be more unforgiving (in
| terms of size fluctuations of the cross-section), but I don't
| see anything that is going to be prohibitive or that will
| make the fiber itself 10x more expensive in the long run.
| Most of the cost of an undersea cable isn't in the silica
| anyway...
| nine_k wrote:
| > _ultra-high power transmission_
|
| Does this mean that such fibers can be used with high-power
| lasers, like those used in tools and weapons?
| GlibMonkeyDeath wrote:
| Yep, that is what funded a lot of this research early on.
| exabrial wrote:
| This is fascinating. As an engineer, my mind always goes to:
| "what are the practical challenges":
|
| * How do you splice without crushing the core?
|
| * How do you terminate/splice and maintain vacuum?
|
| * How do you terminate at all
| frainfreeze wrote:
| tldr: lasers (angry light)
| Ciunkos wrote:
| The article is full of AI slop, sorry.
| londons_explore wrote:
| How do you evacuate these fibers to any decent vacuum?
|
| Sticking a vacuum pump on one end and waiting presumably won't
| work because gas will take a really really long time to diffuse
| along a multi kilometer long micrometer wide tube...
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