Steve Schear wrote...
I haven't checked but assume they should be relatively cheap. For example, I'm assuming this device isn't too expensive and the sensor itself should be available for a few $10s. http://www.ame-corp.com/UVB.htm
Perhaps I misunderstand what you would want to use this device for. Remember we need to detect bits, not just the presence of UV/IR or whatever. It's got to be able to react quickly, and hopefully quickly enough that the electronics behind it can be off-the shelf, and probably Ethernet or SONET-capable. (Think 10/11 Meg, or 155Meg and beyond...)
And because I've never heard of UV-based communications, I would assume that such a receiver would be quite expensive, even at lower bitrates. However, if you go with the standard tele/datacom wavelength bands (850nm, 1310nm, 1550nm...), prices get VERY cheap, even at bandwidths up to OC-48 (2.5 gig). With both the 1550nm as well as 1310nm-band, you have the added possibility of optical amplifiers (Raman at 1310nm, Erbium-Doped fiber amplifiers at 1550nm), and pretty much unlimited power (cladding-pumped fiber amplifiers can output in the 2 to 5 watt range and beyond).
Oh, and it should be mentioned that several companies have already commercialized free-space point-to-point line of sight optical communications at these bandwidths and these wavelegnths, so the only thing you really need is the wierd antenna, and I'd bet there's something out there already you could use.
-TD
And preferably, it would be nice if it could run up to 11Meg/sec or so.
I don't think you will be able to get anywhere near multi-megabit data rates with inexpensive, omni-directional, optical systems. But that's needed for broadcast of entertainment .mp3 sterams.
Seems to me if one wanted broadcast, operating in the 1550-nm range and then using good old EDFAs might work, if one had the right kind of omnidirectional IR 'antenna' (or whatever such a thing would be called). Then of course, the broadcast cost would be kind of expensive (say $5000), but the detectors could be cheap ($100 or less). The only drawback here is fog (1550nm doesn't go too good through fog, but rain and snow are apparently fine).
Fabrication of efficient, high-power,isible wavelength emitters and sensors using nano-imprinting technologies should be feasible today. The advantage of this approach is that it need not employ materials using their bandgaps but simply resonant structures similar to RF circuits.
steve
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