Phase Clusters Induced by Degeneracy in a Phase Locked Fiber Laser Array

We investigate phase-locking of seven fiber lasers coupled in a Talbot configuration. We show that phase clustering occurs in the array whereby the array separates into two different phase-locked clusters. Further, theoretical analysis and experimental measurements show that these clusters result from an incoherent superposition of the in-phase and out-of-phase supermodes of the array. By inserting selective loss in the resonator, we manage to demonstrate operation in a nearly single pure in-phase supermode.