You are not the only one. I know Mellanox
As it is for virtually all other flavours of data transmission at these rates nowadays (Ethernet, Fibre channel, InfiniBand, PCI Express)
My
Others are certainly achieving it at 5Gb/s
What is
You don't seem to have a firm grasp of 8B/10B encoding. I would strongly suggest you look that up first. Note that the running disparity enables a serdes to detect which 'sense' the input signal has been connected and automatically switch the 'p' and 'n' inputs appropriately.
Inherently so, and designed specifically with that in mind. Maximum run length = 5. Strictly speaking, that makes the system 'source synchronous'
Of course. This is a well understood technology (although not necessarily at 10Gb/s)
Another question would be if a PLL at the input
There are PLLs operating well beyond this in a number of areas
Get the background on 8B/10B encoding (part of the IEEE802.x specs), clock recovery techniques (google is your friend) and the latest high speed existing serdes devices. Without that background, I fear you will have a frustrating time.
Cheers
PeteS