Phase Synchronization and Mode Selection in Arrays of Delay-Coupled Semiconductor Lasers

We consider existence and stability of spatial modes of the external cavity of the delay-coupled semiconductor laser diode array and show that such arrays can be almost perfectly phase synchronized when the cavity is designed appropriately. Using an extension of Master Stability Function theory, we show that by using a decayed nonlocal coupling scheme, it is possible to induce robust and close-to-perfect CW and chaotic phase synchronous states. These synchronous states are robust to noise and moderate amounts of frequency disorder between elements. We also find that the critical coupling strength for which the synchronous state destabilizes increases approximately linearly with array size.