Fiber is very often frequency divided to give full duplex on a single strand to customers. Or the concept is taken to the extreme e.g. GPONs.
It is certainly POSSIBLE to do WDM on a PON, but you need separate matched pairs of transceivers for each connection which kind of defeats the purpose (you now need a mux/demux at the end which adds more attenuation to the line, as well as more expensive electronics as you went from needing one GPON port to N Gbe ports). As such, wavelength division is typically used over point-to-point links to get more discrete links over a single fiber (or pair).
There are typically 3 wavelengths.(frequency division). Two for data(downstream and upstream) and one for video (downstream).
The downstream channels(both video and data) are broadcast and not time divided. The streams are filtered by the ONT. The upstream data channel is time divided to permit multiple devices transmitting without collision.