Polarization self-modulation in a VCSEL subject to optical feedback through a quarter-wave plate

The polarization self-modulation observed in VCSELs subject to optical feedback through a quarter-wave plate comes from a Hopf bifurcation located on external cavity mode steady states (ECMs). Two combs of ECMs are created and connections between these two combs are performed through periodic solutions, confirming theoretically a beating process in this system. Our results substantiate previous experimental findings and motivate new investigations.