Electronics

Hybrid fiber optic cable carries data and power

Titus Appel (left) and Steve Sanderson, with their power-over-fiber communications cable
Titus Appel (left) and Steve Sanderson, with their power-over-fiber communications cable

When you want to isolate communications between two devices or locations, a fiber optic link is one of the best ways to go. Under some circumstances, however, you might also want to isolate the transmission of power - in situations where traditional copper wire might prove unsafe or impractical, for instance. That's why researchers at Sandia National Laboratories are developing a power-over-fiber (PoF) communications cable. It carries not only data, but also optical power.

Invented by Sandia's Titus Appel and Steve Sanderson, PoF is currently limited to a fairly low capacity, so don't expect it to be delivering power to your house any time soon. It could, however, supply power to small electrical devices such as sensors, for which it would also be providing data transfer.

In the cable's present incarnation, optical power goes through a single glass fiber. A laser diode at one end of that fiber emits light, while a miniaturized photovoltaic cell at the other end converts it into electricity. Power is only delivered on demand, in order to save energy.

Data is carried by plastic optical fibers, connected to stacked circular circuit boards with LEDs, mounted in the backshell connector housings at either end of the cable. The next version of the PoF will use less-bulky glass fibers for both power and communications. It should also have the ability to provide power to outside devices, whereas the present prototype uses the optical power solely to run its own communications electronics.

So, where would such a cable find use? Appel and Sanderson believe it would be useful in applications relating to safety, such as security, explosives, explosion-proof devices, aviation and medical devices. "The key issue here is to maintain total electrical isolation from any stray electrical energy and high-voltage electrical surges caused by such things as lightning strikes," said Sanderson.

The team have already tested a PoF-based low-energy detonator firing cable, which carries data regarding detonator resistance, temperature and charging voltages, while also delivering power to the detonator. They are now working on reducing the size, weight and cost of the technology, and making it rugged enough to stand up to everyday use.

Source: Sandia National Laboratories

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9 comments
cachurro
It strikes me the article does not mention the current technology called PoE (Power over Ethernet). I guess PoF has the potential to carry more data, for a longer distance, but provide less power.
Sambath Pech
So it\'s essentially like a USB-powered cable?
yawood
Cachurro, you seem to have misunderstood the thrust of the article. PoE runs the power through a pair in the CAT 5 cable which is a copper cable. This article is all about no cable connection but only fibre so this will allow power and data to pass through fibre like PoE allows power and data to pass through a data cable.
Slowburn
This will allow you to hang sensors on lightning rods or high tension wires without frying your computer.
vim99
Would it not be nice that it could be used to supply current to all end user eg houses & factories . Then no more cable theft
Wanzewurld
It\'s going to be quite a while before we come up with a better way to transmit and utilize power for our homes and industry but intermediate steps like this are necessary to realize that goal. I\'m aware the power transmitted is miniscule but it\'s a step in the right direction. We don\'t usually think in terms of \"What if this is done on the scale of millions or billions,\" but that\'s precisely how the transistor started life and evolved into computer chips; this could very well be just that dramatic!
Check out the \"Related Articles\" below to see how relevant it could become!
Andrew Trovato
I can see this being applied to domestic uses like v.o.i.p. phones that use fiber optics to send and receive data. Traditional phone technology still has the advantage of being powered even in a blackout, but this may change that and make v.o.i.p. a more reliable and widely-accepted technology.
Woosnamc
Well the HPCS - Hybrid Power and Communications System has already been invented and furthermore is the basis for the new CSA C22.2 No.267-2010 ASPCA 'Life Safety' Wiring Standard. The disclosures and evidence supplied during the writing of this New Standard furthermore was responsible for the realization of UL and ULC to subsequently cancel all Certifications of FHIT type wiring and 90 C Plenum / Riser type certifications as not adequate to survive a typical fire scenario. The new CSA ASPCA Standard is being adopted around the World currently by IEC, CEC and NEC and represents the largest change in wire safety code in years. It was also the first New Standard to attack and change the UL S139 Communications Standard making BERT the only acceptable testing method for data and communciations integrity in communications circuits in the future. So soory SANDIA you are too little to late for this one.
Woosnamc
By the way Titus and Steve, the new CSA ASPCA or C22.2 No.267-2010 'Life Safety' Wiring Standard means that the cable I submitted for this Standard as an example, carries up to 100 Amps, 600 VAC and 3 GigE optical lines, but survives in 2000 F temperatures, over 500 lbs crush resistance, is hydrophobic and will withstand 2600 lbs tension. It comes in Connectorized Segment lengths 5 ft to 3000 ft in length and marries to the HPCS Junction Box for full access and infinite length extension. Sure surpising that the UL with instigated the New Standard after seeing supporting evidence of this product, took until late 2012 to renounce the current FHIT and Riser / Plenum (90 C) certifications as Not meeting Fire Safety Standards.