Abstract

Injection-locking of isolated semiconductor lasers has been studied to a considerable extent (see for example [1]), but here we are concerned with an array of lasers. The analytical study of phase-locking via an external tunable source of a multiple element system acting as the slave component is important from the point of view of understanding how the intrinsically out-of-phase operation of evanescently coupled semiconductor laser arrays is modified to produce in-phase operation at both weak inter-slave clement coupling strengths and low injection levels. In this study we are concerned with small numbers of slave elements arranged, in particular, in two-dimensional lattices. The inclusion of carrier dynamics is essential to the understanding of the stable locking regimes and although this limits the analytical progress possible we have established; using the time-dependant coupled mode semiconductor laser rate equations, the locked equilibria of the injected two-clement and three-element (cyclic) slave systems allowing for additional inter-slave detuning. In addition the locking bandwidths and locked phases are described. In particular the transition from an out-of-phase slave system to an in-phase locked system with the resulting single lobed far-field distribution is characterised and found to occur at very low (≃−80dB) injection levels.

© 1996 IEEE