Influence of weak optical feedback on the polarization performances of current-modulated VCSELs

Abstract

Based on the framework of the spin-flip model (SFM), for the GHz level modulation frequency, the polarization performances of current-modulated vertical-cavity surface emitting lasers (VCSELs) subject to weak optical feedback have been theoretically investigated. The results show that, for type I polarization switching (PS), under small signal modulation, the variation of the modulation frequency does not affect the polarization direction of the VCSEL output, but due to the influence of the optical feedback, the VCSEL output may behave period, doubling period and chaos state with modulation frequency variation. For the case of the large signal modulation, optical feedback can result in the generation of a new style of PS with the variation of the modulation frequency.