Lasing Characteristics of VCSELs Subject to Circularly Polarized Optical Injection

This paper reports experimental investigations of the effects of circularly polarized optical injection on the lasing characteristics of vertical-cavity surface-emitting lasers (VCSELs). The operating characteristics of the target VCSELs are changed using available optical injection control parameters including the strength and polarization state of the optical injection as well as the frequency detuning between the injected light and the target VCSEL. Using circularly polarized optical injection with frequency detuning around -10 GHz, the linear output polarization of the stand-alone VCSEL can be converted into circularly polarized or elliptically polarized emission when the VCSEL drive current is close to or below the threshold current of stand-alone VCSEL. In addition, highly nonlinear light-current characteristics are observed in the optically injected VCSEL in the vicinity of threshold.