Quickly obtaining degree of polarisation ellipsoid by using particle swarm optimisation

Degree of polarisation (DOP) ellipsoid obtained by using a polarisation scrambler is a good PMD monitoring signal, which can determine both the differential group delay (DGD) and the principal states of polarisation (PSP) by its three radii and the orientation angle of ellipsoid. Generally, getting a correct DOP ellipsoid need to collect more than several thousands of sampling data of states of polarisation (SOP), which results in an unacceptable time consuming for adaptive PMD compensation. In this paper, using particle swarm optimisation (PSO) algorithm as data fitting algorithm, the DOP ellipsoid was obtained only using 100 sampling points within 150 ms. The values of DGD and the direction of principal states of polarisation (PSP) obtained from the DOP ellipsoid by data fitting are accurately. The results show that the PSO algorithm was effective for ellipsoid data fitting with high precision and less time consuming.