Hi friends:
FTTH: is a service that aims to send and receive data from the client at home to the exchange via fiber cables to take advantage of the high speeds.
FTTH Architecture:

FTTH components:
the FTTH consists of seven major components:
Core components:
ONT
OLT
U2000
Supplimental components:
ODN
TMS
Valued Added components:
N2510
uTraffic
WDM: is a technology aims to collect more data and transfer them at high speeds on a single fiber cable by placing all of them on a specific frequency / wavelength and collecting them through an optical multiplexer.
A WDM system consists of many functional units, such as the OTU, which is used to forward client-side data services to the line-side optical interface. An optical multiplexer unit (OMU) and an optical demultiplexer unit (ODU), respectively, are used to combine and separate multiple wavelength optical signals. Optical amplifier (OBA), optical line amplifier (OLA), and optical preamplifier (OPA) are used to amplify optical signals at the transmit end, link, and receive end. The optical supervisory channel (OSC) should also be included to monitor services and links for network management and maintenance.
OTU
OTUs convert received non-standard wavelengths into ITU-T-compliant wavelengths by performing O/E/O conversions.
OMs
OMs are deployed at the transmit end of the WDM system. An OM has multiple input ports but only one output port. Each input port receives one optical signal (wavelength). After multiplexing all the input wavelengths, the OM sends out the multiplexed wavelength through its output port, providing for transmission of multiple optical signals over the same fiber.
ODs:
ODs are deployed at the receiving end of the WDM system. Each OD has only one input port but several output ports. Opposite to an OM, an OD splits multiple wavelengths apart and sends them out through different output ports.
OA
OAs directly amplify optical signals to compensate for line attenuation, ensuring that optical signals can propagate over a long distance. OAs are indispensable parts of fiber communication systems.
OSC
The OSC channel is used to monitor the WDM transmission system performance. The OSC channel is multiplexed into the main channel after the main channel leaves the OA at the transmit end and split from the main channel before the main channel enters the OA at the receiving end.
Now we can recognize the diference between FTTH and WDM:
FTTH is a technology that is being used on the part of the client
WDM technology is used inside the backbone network
FTTH technology follows access transmission
WDM technology is called backbone Transmission
Thank you.

