"Talking of which, John looked up the latency of the two Atlantic cables; the shorter journey clocks up a round trip delay (RTD) of 66.5ms, while the longer route takes 66.9ms. So your data is travelling at around 437,295,816 mph. Fast enough for you?"
Too fast. Like breaking the law fast.
Edit: oops my bad. That's mph and c is 186k miles per second. So this is like 0.66c - nothing to see here, move along!
There's another interesting (at least to me) calculation there.
From the article:
6,500km cable length
148 (& 149) amplifiers
66.5 (& 66.9) ms of round trip latency
Wikipedia says the refractive index of typical optical fibres is 1.44
So the light travel time down 6500km of fibre would be 6,500x10^3/(3^10^8*1.44) = 0.0312ms, and twice that for the round trip = 62.4ms
From that we get that the total latency of 66.5ms is 62.4ms of light travel time plus 4.1ms of (presumably) inline amplifier and terminating equipment latency.
That means each of the 148 amplifiers are doing their thing in something less than 28 microseconds, possibly way less since it'd be easy to assume the terminating equipment at each end is doing a way more time consuming task that just amplifying the signal, so could easily be taking up the bulk of that 4.1ms non-travel-time latency.
Basically, the repeater is another laser, but the emmission of new photons is stimulated by low-energy photons exciting the partially-excited atoms in the amplifier.
There are different types of amplifiers, you can look it up on wikipedia. All those amplifiers introduce way less than 28 micro of latency. I would attribute those 4100 micros mostly to landing sites.
"Talking of which, John looked up the latency of the two Atlantic cables; the shorter journey clocks up a round trip delay (RTD) of 66.5ms, while the longer route takes 66.9ms. So your data is travelling at around 437,295,816 mph. Fast enough for you?"
Too fast. Like breaking the law fast.
Edit: oops my bad. That's mph and c is 186k miles per second. So this is like 0.66c - nothing to see here, move along!