[Nick Danger]

tapping into, fiber optic cable. This is a very tricky task, considering the high voltage running through the cable

[Covenantor]

Yeah, set my meter off too.

[Bogey78O]

Fiber has a loss every couple of miles that needs a boost. It's possible they use underwater repeater cases which require power.

[quidnunc]

I think they need electrical power for switching junctions too.

[Cornpone]

"Notes: The person from whom I originally received this article was immediately sceptical of the reports of magnetic fields from fiber optic cables. But unlike short-haul terrestrial fiber cables, where the fiber would not emit any fields, undersea cables must carry high voltage power to the undersea repeaters, which would result in both electric and magnetic fields around and along the cable."

http://yarchive.net/phone/oceanic_cable.html

[DugMac]

The fiber optic cables would not carry any voltage (other than occasional static) the repeaters would be powered but would then go through a electrical to optical interface (converter if you will) where once again the signal is purely optical. BS Indeed!

[eno_]

Just about EVERYTHING in this article is wrong:

1. You can splice into a submarine cable, but it is difficult to do and easy to detect.

2. There IS power in the cable (unless it is a very short-distance cable, and it used to power repeaters. In fact, the place to "splice in" is at these repeaters since there is no need to splice the fiber at all. Instead, you tap in to the repeater's electronics.

3. You would not "park" a submarine to gather intelligence for more than a very short time. You would run your own submarine cable to backhaul the tapped bitstream.

4. I think all of this crap about tapping submarine cables is a cover story. The way you do it in real life is you bribe someone to let you tap in at a landing point or a SONET switch on land. You backhaul on another lambda to a friendlier place.

[expat_panama]

You may want to recalibrate your meter.

An Oversimplified Overview of Undersea Cable Systems

Power on repeatered cables

When repeaters are needed they must be powered. The standard approach is to send a constant current of about 1A from one end of the cable to the other, along a copper sheath, which lies outside the Fibers and inside the armour (if present). Each km of cable offers a resistance of some 0.7 ohm, and the voltage drop across each repeater is typically 40V (on four Fiber-pair cable), leading to a requirement of close to 10 KV across a typical 7500 km transatlantic crossing with 100 repeaters. In branched cable systems the power management becomes somewhat more complex, and the branching units incorporate very high reliability relays to cope with the power reconfiguration needed in case of repairs.

[6SJ7]

Bingo! Voltage? What voltage? Just us photons here!

For that matter, I don't think one taps a fiber line like a conventional phone line. You can cut and splice fiber, but you can't apply a 'T' tap.