Polarisation Dynamics of Quantum Dot VCSELs: Proposal to support Visiting Researcher Dr. D. Alexandropoulos

In recent years polarisation dynamics in vertical cavity surface-emitting lasers (VCSELs) has been the subject of considerable research effort. A wide range of phenomena including polarisation switching, bistability, limit cycles and chaos has been studied theoretically and experimentally in VCSELs subject to orthogonal optical injection. The active regions of these VCSELs have consisted of bulk or quantum well (QW) material. At the same time, there have been significant advances in the technology of quantum dot (QD) VCSELs, whose key advantages include an excitonic gain mechanism, suppressed carrier diffusion and low degradation rate. Recent research has concentrated on development of QD gain media to give ultrahigh modal gain and enhanced modulation response. Novel VCSEL cavity designs have also been developed to suppress parasitic modes which can cause gain depletion and self-pulsation. However, there are as yet very few reports of polarisation-dependent effects for these QD VCSELs. The theoretical study of polarised optical injection in QD VCSELs that is proposed here represents an entirely new research direction of fundamental importance that is certain to further enhance the UK's optoelectronics research profile.