Abstract
Transmission performance is improving through the use of new modulation formats such as multi-level PSK, OFDM and coherent detection. ROADM, WSS, OXC and optical packet switching have been exploited for the node of fiber ring or mesh network topology to overcome the bottleneck of optical network. This paper reviews recent advances in optical devices for long haul and metropolitan area networks and describes milestones in optical technology. These developments in optical technology allow us to expand the broadband networks. Moreover, the progress made on photonic device performance enhances system performance.
