Controlling VCSEL polarization by monolithically integrated surface gratings: a survey of modelling and experimental activities

VCSELs have several advantages with respect to edge emitting semiconductor lasers; their major drawback is the lack of polarization control due to the almost absence of any selecting mechanism in the resonator and active medium. In this paper we will review a technique based on the integration of a shallow grating into the VCSEL output facet, which gives very good results, provided that a careful design is performed.