Scientific American on Quantum Encryption

Trei, Peter ptrei at
Thu Jan 20 08:35:47 PST 2005

Eugen Leitl wrote:

> On Thu, Jan 20, 2005 at 10:47:38AM -0500, Trei, Peter wrote:
> > I've actually seen these devices in operation. The thing
> > that impressed me most was that the path need not be a
> > single fiber from end to end - you can maintain quantum
> > state across a switchable fiber junction. This means
> Very impressive. If they manage to keep the entanglement all
> the way up to
> LEO by line of sight it would be even more impressive
> (anyone thinks this can be done at all?)
> > you are no longer limited to a single pair of boxes talking to
> > each other.

At the moment, the practical limit in fiber is around 150 km

Getting to LEO is a *lot* harder - remember, you're throwing
and catching one photon at a time - a beam that spreads wider than
your detector is usually going to miss the detector.

Peter Trei

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