about the appliction of pll/cdr in sonnet/sata/ether/usb

I just know that pll is a very import part in the optical communication.

1. but don't know if it is also used in usb/sata/ethernet..... those application bellow 1Ghz?

2.My instructor tell me that it not nessarily to study some matters like 1/2 1/4 1/8 phase detetor/multiphase vco..., actually I am somewhat doubting about it, can anyone tell me that for 40Gb/s or higher optical application is these technique widely adopted by industry?

3.do these application such as sata/usb/ethernet also adopt architechure like

transmitter:
power amplifier/driver(such as laser driver)

receiver:
a low reamplifier(tia)
a limiting amplifier like chain plus dc offset calibration loop
+cdr....