Weakly coherent optical systems using lasers with significant phase noise

Current theories for coherent receiver performance as affected by phase noise are compared, the main prediction of these theories are highlighted, and the reasons why many coherent system experiments have failed to approach the level of performance which is theoretically possible are considered. Different theoretical predictions are compared under idealized receiver conditions concerning the appropriate IF bandwidth, the penalty in receiver sensitivity resulting from laser phase noise, and other system properties. In general, good agreement is found. It is shown how these results differ for realistic receiver parameters, and optimized front-end design using tuning of parasitics is suggested