Review of new technologies in “Green” optical network

Though introducing the conception of “green” to optical networks, we discuss three key technologies to enhance the network energy efficiency rate (NEER), including General Multiple Protocols Label Switch (GMPLS), Passive Optical Network (PON), and Network Redundant Element Shutdown (NRES) technology. The optimization and improvement methods as well as the situation of application of the three technologies are analyzed. Then we explore the prospective development of the green optical networks.