Polarization switching of transverse modes in VCSELs subject to two-frequency orthogonal optical injection

Abstract

We report a theoretical study of the polarization and transverse mode properties of single and multi-transverse mode VCSELs when they are subject to two-frequency, or dual-beam, orthogonal optical injection. We analyze the nonlinear dynamics of the system making special emphasis in the double injection locking observed at large injection strengths, useful for photonic microwave signal generation. Simulation of single and multi-transverse mode VCSELs show that the double injection locking can be obtained when these devices are subject to dual-beam orthogonal optical injection. We show that the extra degree of freedom given by the multi-transverse mode operation of the VCSEL under dual-beam orthogonal optical injection is useful for enhancing the performance of the photonic microwave generation system. In fact we obtain that the higher-order transverse mode is excited with a much larger amplitude than that of the fundamental transverse mode. The response of the multi-transverse mode VCSEL is enhanced with respect to that obtained with a similar single-transverse mode VCSEL subject to the same dual-beam orthogonal optical injection. Wide tuning ranges, beyond the THz region, and narrow linewidths are also demonstrated in our system.