4 ms·
submarine cables are significantly different than terrestrial fiber networks. a fault will be detected in/from both directions, immediately and automatically.
by pyvpx 11y ago
submarine cables are significantly different than terrestrial fiber networks. a fault will be detected in/from both directions, immediately and automatically.
it has been suggested that the USS Jimmy Carter can tap submarine cables without disrupting service or physically damaging the fiber.
did you know when you bend a strand of fiber enough, you can make out the signal and only affect attenuation?
- mschuster91 11y agoYeah but still you need to remove the outer casing in order to, well, see the fiber. And that is detectable if you have to cut through a layer conducting high voltage.
- Mtinie 11y ago"Where there's a will (and enough black project money), there's a way." With love, NSA
- thowawy3216 11y agoModern cables don't have high voltage to worry about. The signals are amplified optically: https://en.wikipedia.org/wiki/Optical_amplifier#Doped_fiber_amplifiers https://en.wikipedia.org/wiki/Optical_amplifier#Doped_fiber_... It isn't necessary to bend a fiber either. Optical fibers can be tapped via evanescent wave coupling. The fiber cores just need to be near enough to each other over a long enough span, possibly with some removal of the outer cladding. Notable patents: "There is a need for coupling light into and from an optical transmission line without interrupting the flow of transmission. Such lines may be used for communications, as well as other purposes.[1]" 1. https://www.google.com/patents/US3933410 https://www.google.com/patents/US3933410 2. https://www.google.com/patents/US4097117 https://www.google.com/patents/US4097117 3. https://www.google.com/patents/US4377403 https://www.google.com/patents/US4377403 4. https://www.google.com/patents/US4763272 https://www.google.com/patents/US4763272 5. https://www.google.com/patents/US4336047 https://www.google.com/patents/US4336047
- kijiki 11y agoRaman amplifiers still require juice to run the pumping laser. There aren't exactly 110V sockets sitting on the ocean floor. There is a copper tube around the fiber bundle that carries high voltage (usually 10,000+ volts to reduce losses over long spans). The return is usually just coupled directly to the ocean. If you're careful, use a non-conductive cutting blade, and have enormous balls, you can no doubt cut through the tube on one side and not cause any noticeable effects. At least, if you've brought along someplace dry to work on it...
- mmmBacon 11y agoYeah it's just not that easy with the advent of coherent optical communications in subsea networks. You need to be able to do some very complex DSP in real-time at 50Gb/s. You also need to know the exact FEC encoding scheme, grey map, actual modulation format etc... It is very non-trivial. For OOK signals I think it's somewhat doable for coherent, very, very hard. Not totally impossible but I highly doubt even CIA has this expertise.
- zw123456 11y agoSubmarine cable is nitrogen doped to prevent hydrogen intrusion.