Optical Performance Monitoring for Fiber-Optic Communication Networks

Optical performance monitoring (OPM) is an enabling technology and a potential mechanism for the control, management, and maintenance of existing and future high-speed reconfigurable optical networks. This chapter discusses some common features expected from the OPM techniques. The existing OPM techniques for direct detection fiber-optic networks assume either prior information about the signal's bit rate and modulation format or the attainment of this knowledge from the upper layer protocols. However, practically it is not feasible to introduce additional cross-layer communication for OPM purposes at the intermediate network nodes because these nodes can only handle limited complexity. Therefore, it is crucial to have the capability of joint bit rate and modulation format identification (BR-MFI) at the intermediate network nodes since the OPM techniques used at these nodes may be bit rate/modulation format dependent.