850 nm VCSEL array for decoy state quantum key distribution

Quantum key distribution (QKD) offers the advantage of secure data communication based on the laws of physics. However, the application of single photons and hence true single photon sources comes along with sophisticated operation schemes and bulky device sizes, hindering their large-scale implementation. Offering a small device foot print and low power consumption, VCSELs represent an excellent candidate for a light source for satellite based QKD via the decoy state protocol. In this study we present recent results of an eight VCSEL array at an emission wavelength of 850 nm with integrated subwavelength polarization gratings for polarization control.