If you're talking about a WDM element or passive splitter or other purely optical component, then you'd need some kind of error correction (in the digital domain) in order to overcome the fact that many of the photons will not choose to go in the direction you want.
In the long run I think we'll see some small proliferation, but given the level of integration and how well current coding schemes work, I'd guess this will remain a niche unless there's a major breakthrough in factoring.
-TD
From: "Trei, Peter" <[EMAIL PROTECTED]> To: "Eugen Leitl" <[EMAIL PROTECTED]>, <[EMAIL PROTECTED]> CC: <[EMAIL PROTECTED]> Subject: RE: Scientific American on Quantum Encryption Date: Thu, 20 Jan 2005 10:47:38 -0500
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 you are no longer limited to a single pair of boxes talking to each other.
True, the SciAm article doesn't address a lot of issues, but the fact remains that this technology is interesting and important.
Peter Trei
> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] Behalf Of Eugen Leitl > Sent: Thursday, January 20, 2005 6:17 AM > To: [EMAIL PROTECTED] > Cc: [EMAIL PROTECTED] > Subject: Scientific American on Quantum Encryption > > > > Scientific American has little clue, as usual (see their > nanotechnology > retraction). > > Link: http://slashdot.org/article.pl?sid=05/01/20/0358215 > Posted by: samzenpus, on 2005-01-20 06:35:00 > > from the just-try-and-break-it dept. > [1]prostoalex writes "Scientific American claims that > [2]advances in > commercially available quantum encryption might obsolete > the existing > factorization-based solutions: "The National Security > Agency or one of > the Federal Reserve banks can now buy a > quantum-cryptographic system > from two small companies - and more products are on the > way. This new > method of encryption represents the first major commercial > implementation for what has become known as quantum information > science, which blends quantum mechanics and information theory. The > ultimate technology to emerge from the field may be a > quantum computer > so powerful that the only way to protect against its prodigious > code-breaking capability may be to deploy quantum-cryptographic > techniques.""
