Polarization Effects on Photonic Microwave Generation in VCSELs Under Optical Injection

Photonic microwave generation is studied theoretically in a single-transverse mode VCSEL subject to parallel optical injection. We focus on the dependence of microwave power and frequency on the frequency detuning. We find that, for a fixed injection power, the microwave power at the fundamental frequency is maximum for two different values of the frequency detuning. These results agree qualitatively with those found in recent experiments using optically injected VCSELs. The two maximum microwave powers appear because of the out-of-phase excitation with small amplitudes of both linear polarizations of the VCSEL for frequency detuning between the values at which the two maxima appear.