So I'm a hardware engineer learning about networks, and one interesting subject that my book glassed over was how hybrid fiber-coax networks work. One thing that was throwing me off was that the analog signals on the coax were being converted to light at fiber nodes then sent to the local head end--I had been under the impression that fiber was always digital.
The relevant wikipedia article mentions the use of broadband optical transmitters, but doesn't elaborate on their function. The lasers and transistor detectors that make up digital links make sense to me, but analog doesn't seem obvious. Lasers/LEDs cant be frequency modulated, so instead are they intensity modulated? How do the channels get muxed in and out of the fiber? If they don't get muxed before the detector, how does each photodiode tuned to detect a given channel?