Chaos synchronization in vertical-cavity surface-emitting laser based on rotated polarization-preserved optical feedback

In this paper, the influence of the rotating polarization-preserved optical feedback on the chaos synchronization of a vertical-cavity surface-emitting laser (VCSEL) is investigated experimentally. Two VCSELs'polarization modes (XP) and (YP) are gradually rotated and re-injected back into the VCSEL. The anti-phase dynamicssynchronization of the two polarization modes is evaluated using the cross-correlation function. For a fixed optical feedback, a clear relationship is found between the cross-correlation coefficient and the polarization angle θp. It is shown that high-quality anti-phase polarization-resolved chaos synchronization is achieved at higher values of θp. The maximum value of the cross-correlation coefficient achieved is −0.99 with a zero time delay over a wide range of θp beyond 65° with a poor synchronizationdynamic at θp less than 65°. Furthermore, it is observed that the antiphase irregular oscillation of the XP and YP modes changes with θp. VCSEL under the rotating polarizationoptical feedback can be a good candidate as a chaotic synchronization source for a secure communication system.