This project aims at developing novel techniques that upgrade existing E-PON network infrastructures in order to meet the requirements of new demanding services (i.e. video on demand) in terms of both bitrate and QoS. A significant target is scalability avoiding dramatic modifications of the network. The upgrade refers to physical layer of E-PON network and is based on the low-cost technique of orthogonal modulation by combining two modulation formats, namely intensity modulation and frequency shift keying, at the same optical carrier.