  Recently it is shown that dissipatively coupled laser arrays simulate the
classical XY model. We show that phase-locking of laser arrays can give rise to
the spontaneous formation of vortex and antivortex phase patterns that are
analogous to topological defects of the XY model. These patterns are stable
although their formation is less likely in comparison to the ground state
lasing mode. In addition, we show that small ratios of photon-to-gain lifetime
destabilizes vortex and antivortex phase patterns. These findings are important
for studying topological effects in optics as well as for designing laser array
devices.
