FTTx involve optical networks, depending on network capacity and reach it covers:
- Passive Optical Networks (PON) - cheap, but bit rates are about 10 Gbps and the reach of a fibre span can be tens of kilometres.
- Active Optical Networks (AON) - allows achieving high bit rates over 1 Tbps by employing DWDM systems:
- Solve topology, attenuation, dispersion and nonlinear issues – network planning.
- Channel rate at least 100 Gbps.
- Run at least 40 G DWDM over 10 G DWDM.
- Potential coexistence or convergence of different systems with different specifications.