Analysis of free-space optical interconnect misalignment tolerance in the presence of multimode VCSEL beams

Successful deployment of free-space optical interconnects (FSOIs) primarily depends on their tolerance to misalignment. In most misalignment studies done so far, laser beams were assumed to have purely Gaussian intensity distributions. We experimentally show that this is not the case, and that FSOI misalignment tolerance halves if less than 80% of the optical power is in the fundamental Gaussian mode.