ABSTRACT
The simpler way to respect the Compatibility Conditions seems to be through the exploitation of wavelength division multiplexing (WDM) technology starting from the ITU-T standard allocation of the fiber bandwidth in the access area. The different cost trends, with volume offered by hybrid and integrated technologies, are an advantage that could be precious in the long run, when passive optical network (PON) volumes go up unavoidably. Differently from gigabit passive optical network, WDM-PON needs one optical interface per user not only in the optical network unit but also in the optical line terminal. For this reason, optical interface technology is a key in implementing a cost-effective WDM-PON. The Photonic Integrated Circuits is also the approach to try to reduce interface costs in XWDM-PON. It is to underline that the first photonics integrated circuit prototypes were realized at 10 Gbit/s either for application in the digital optical network or simply to reduce the cost of metro equipment.
