A peek in the TGN fiber optic submarine cables

[mudmanc4]

Very nice glimpse into the global fiber optic submarine networking cable.

 

Quote

“Forward error correction is used to understand the signal that’s being sent, and modulation techniques have changed as the amount of traffic going down the signal has increased," says Osborne. “QPSK [Quadrature Phase Shift Keying] and BPSK [Binary Phase Shift Keying], sometimes called PRK [Phase Reversal Keying] or 2PSK, are the long distance modulation techniques. 16QAM [Quadrature Amplitude Modulation] would be used on a shorter length subsea cable system, and they’re bringing in 8QAM technology to fit in between 16QAM and BPSK.”

DWDM (Dense Wavelength Division Multiplexing) technology is used to combine the various data channels, and by transmitting these signals at different wavelengths—different coloured light within a specific spectrum—down the fibre optic cable, it effectively creates multiple virtual-fibre channels. In doing so the carrying capacity of the fibre is dramatically increased.

 

Currently, each of the four pairs has a capacity of 10 terabits per second (Tbps), amounting to a total of 40Tbps on the TGN-A cable. At the time, a figure of 8Tbps was the current lit capacity on this Tata network cable. As new customers come on stream they’ll nibble away at the spare capacity, but we're not about to run out: there’s still 80 percent to go, and another encoding or multiplexing enhancement will most likely be able increase the throughput capabilities in years to come.

Source

 

A couple of example cables:



 

Below is a "deep cable"; where the tiny colored fibers are the trans global fiber network, same as above, without the shallow sea armor. 

 





 

 

 

 

 

 

 



[mudmanc4]

Fascinating, to say the least.