We propose a non-autonomous dynamical system for an optically modulated CO2 laser and show that it exhibits hyperchaos in presence of electro-optic feedback beams. The system is then used to study the synchronization in networks of mutually coupled hyperchaotic CO2 lasers. By the method of master stability function it is shown that the stable synchronous state can be reached for both the ring of diffusively coupled and star-coupled networks of at most 24 nodes or oscillators. However, in the former networks, high-coupling strengths (∼10) are required for synchronization compared to the latter ones (∼1). A numerical simulation of the coupled 24 hyperchaotic CO2 lasers is also performed to show that the corresponding synchronization error ≲10−6. Furthermore, the chimera states of the networks are found to coexist in some intervals of time and the coupling strengths where the networks are not synchronized, implying that the synchronization occurs only in some specific ranges of values of the coupling strengths.