jbn@glacier.STANFORD.EDU (John B. Nagle) (07/29/88)
Some recent work at Stanford on solar cells has produced experimental
units with around 30% efficiency. (This is not something that I'm involved
with; I just happened to hear about it.) These are considered "concentrator
cells", for they work at higher light intensities than sunlight, and thus would
be used with collecting optics in solar energy applications.
The solar energy applications aside, devices like this open up the
possibility of performing power distribution within electronic systems
via optical means. While there are efficiency penalties, in situations
where other considerations predominate, such as RFI/EMI, EMP immunity,
electrical safety, and explosion prevention, there will be a role for
optical power distribution. From operating rooms to jet fighters, from
fuel storage tanks to high-end audio equipment, the advantages of optical
power distribution, coupled with fiber-optic signal cabling, offer
advantages over traditional electrical conductors.
John Naglehenry@utzoo.uucp (Henry Spencer) (07/30/88)
In article <17588@glacier.STANFORD.EDU> jbn@glacier.UUCP (John B. Nagle) writes: > Some recent work at Stanford on solar cells has produced experimental >units with around 30% efficiency... devices like this open up the >possibility of performing power distribution within electronic systems >via optical means... As I recall, several years ago Bell Labs demonstrated a fiber-optic phone that got all its power by photovoltaic conversion of light from its fiber. -- MSDOS is not dead, it just | Henry Spencer at U of Toronto Zoology smells that way. | uunet!mnetor!utzoo!henry henry@zoo.toronto.edu
anand@vax1.acs.udel.EDU (Anand Iyengar) (07/30/88)
In article <17588@glacier.STANFORD.EDU> jbn@glacier.UUCP (John B. Nagle) writes: > Some recent work at Stanford on solar cells has produced experimental ... >possibility of performing power distribution within electronic systems >via optical means. While there are efficiency penalties, in situations What efficiency do we have on the generation side? Anand.
rpw3@amdcad.AMD.COM (Rob Warnock) (07/31/88)
Quite a few years ago, Bell Labs put together a "fiber optic telephone", in
which a single fiber was used for *both* bi-directional signal *and* power
supply, over (as I recall) a several kilometer fiebr-optic cable. The phone
looked like an ordinary "desk set" (you know, type 2500), except it had this
piece of fiber coming out going to a spool of the stuff.
The article said that they were using a form of TDM on the fiber -- somewhat
like the "ping-pong" versions of ISDN -- wherein more than 90% of the time
was outgoing "power", and the rest of the time was input signal pulse
(with guard "dead time" around it). The outgoing "signal" was carried
by position-modulation of one edge of the "power" signal. They spent a
lot of time talking about the trouble they went to building a ringer with
enough efficiency to make an acceptably loud sound with the small amount
of power that was available. (The power for the signal electronics was much
less of a problem!)
Cute...
(Of course, there's no way to plug in an "extension" phone without a
locally-powered repeater.)
Rob Warnock
Systems Architecture Consultant
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