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From: Don Y <blockedofcourse@foo.invalid>
Newsgroups: sci.electronics.design
Subject: Re: For the smart guys/girls/what-have-you here: "Towards a European
 quantum internet"
Date: Fri, 1 Nov 2024 10:17:03 -0700
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On 11/1/2024 1:24 AM, Carlos E.R. wrote:
> If photons at a distance are entangled, what is the optical fibre needed for? I 
> must be missing something.

Otherwise, only the two "endpoints" would be connected; the fiber(s) lets
it become a LAN at *each* end (so multiple devices can share the "quantum
bridge" between the two endpoints.

Imagine a microwave link between two locations.  How would you augment
that to allow more than two hosts (one at each end) to communicate?

The entangled photons represent a secure link "across space".  It's
as if the two ends were colocated (unlike a microwave link -- or any
other medium -- that could be snooped).  The fibers let other devices
exploit that security (as long as the *local* deployments take steps
to preserve THEIR security).