Re: Speed
They don't, just like 40 and 100Gbit/s don't. 40gbit runs at 4 x 10gbit channels (4 optics) 100gbit runs at 4 x 28gbit/s (first attempts were 10 x 10gbit, with the 10gbit channels being a dead-end now). This will now probably be using the 4 x 100gbit channel.
These channels will then have an encoding scheme such as QPSK (there are higher ones too), with this each transmitted symbol represents 2 bits.
Biting the hand that feeds IT
