A BROAD-AREA MODE-COUPLING MODEL FOR MULTIPLE-STRIPE SEMICONDUCTOR-LASERS

We present an analytical perturbation model for calculating the eigenmodes of multistripe diode laser arrays. In contrast to the supermode theory, we develop the array modes into a linear combination of broad-area modes instead of individual waveguide modes. Two perturbations from which mode coupling originates are taken into account, namely, 1) the periodic gain and index grating formed by the current stripes and 2) the effect of temperature variations across the junction. Results of this model are shown to be in excellent agreement with the experimental data, particularly concerning the details of the far-field structure of free-running diode arrays. Furthermore, this model provides a new physical interpretation of the coupling of modes due to temperature variations across the array width. © 1990 IEEE