Phase noise compensation for long-haul coherent optical communication systems using OFDM

摘要

Long-haul optical transmission systems employing coherent optical orthogonaludfrequency division multiplexing (CO-OFDM) are sensitive to laser phase noise. Thisudcauses a common phase rotation and inter-carrier interference. An effective method toudcompensate for the phase noise is to insert an RF-pilot tone in the middle of the OFDMudsignal. This RF-pilot is used to reverse the phase distortion at the receiver.udThis thesis presents a detailed performance analysis of the RF-pilot phase noiseudcompensation scheme in a simulated 64 Gbit/s CO-OFDM system. The effects of variousudparameters including laser linewidth, Mach-Zehnder modulator drive power, pilot-tosignaludratio, and fiber launch power are investigated. A comparison with the pilot-aidedudcommon phase error compensation method is provided to show the differences in theudBER performance with respect to the required overhead.