Study of Orthogonal Modulation Schemes for Passive Optical Access Networks

In this thesis, the potential of upgrading Passive Optical Networks in order to increase available bandwidth and expand in services and number of users is studied. The upgrade is feasible through the adoption of orthogonal modulation techniques –used in other types of networksadapted adequately to the specific needs of a passive optical network. At first, it is investigated and recorded the status of access networks and the technologies used so far as well as the benefits of fiber optics in the access “part” of a network. Furthermore, we evaluated through numerical simulations the use of orthogonal modulation techniques in future passive optical networks. The results of the simulation process lead to the experimental investigation of the transportation of two optical signals on the same optical carrier. Laboratory experiments showed that the use of orthogonal modulation in future passive optical networks is feasible and help us upgrade the already installed networks. Finally, the technological and economical aspects of the passive optical networks upgrade has been investigated and cost elements of this upgrade has been reported, based on the use of IM/FSK technique.