[jthrowsitaway]

Indeed. Not sure why that term is misused so much. There's nothing dark about fiber that's being used.

> A dark fibre or unlit fibre is an unused optical fibre, available for use in fibre-optic communication

[zw123456]

My favorite smart ass response when someone asks me what dark fiber is: Evil Fiber

But seriously, it is just a term of art, when one carrier sub-leases fiber without any terminating equipment and they provide their own equipment to light the fiber. It is "dark" from the standpoint of the provider, they are not "lighting" it. The customer is. Typically the fiber is leased using something called an IRU indefeasible right to use. Basically "condo-ised" fiber.

[rstat1]

At least "dark fiber" isn't a complete lie, like some other tech terms are (Looking at you "serverless")

[exikyut]

Ooooooh. I thought "dark" was some weird domain-specific nomenclature to describe "not available on the open market", with the open market being like a transport network of (lit up) lines, and dark = not lit up = not on the open market.

Now I actually understand the definition I'd say "unlit fiber" feels like a better-resolved way of putting it, although I could see the uninitiated imagining that describing a service that needed an additional subscription on top or something, which isn't quite the right nuance.

[toast0]

More or less, someone with a cable leases you dark fiber, and then you light it. What are you using? lit fiber (obviously), what did you lease? dark fiber.

When it's severed, it's not exactly lit anymore either ;)

[dpe82]

By that logic, all fiber is "dark fiber". :)

As I recall, "dark fiber" came into use after the dotcom bust left lots of overbuilt and unused network infrastructure around that companies could buy up for years after for pennies on the dollar. Buying "dark fiber" in that context had meaning - it meant you were buying already built-out and unused fiber, compared to running your own fiber lines at full cost as had previously been more common.

[sophacles]

> When it's severed, it's not exactly lit anymore either ;)

It literally is lit though, the lasers at both ends are still trying to send bits, or at least sending pulses to do fault location.

[escapecharacter]

oh, so dark matter is like unused matter. Got it.