Voltage Spectroscopy and the Operating State of an Optically Injected Long Wavelength VCSEL

A study on the correspondence between the voltage and optical properties of long wavelength vertical cavity surface-emitting lasers (VCSELs) during tuned optical injection is presented. A direct link between the voltage response and the induced optical dynamics for parallel and orthogonal injection is highlighted. The induced dynamics include unlocked stable polarization switching at large frequency offsets from the free-running VCSEL lasing wavelength for both injection orientations. The carrier density change during stable locking is estimated using the cavity resonance shift and voltage change. This estimate is confirmed using a full numerical simulation of the injection locked rate equations.