Effective reflectivity from self-imaging in a Talbot cavity and its effect on the threshold of a finite 2-D surface emitting laser array

UNLABELLED: Using a self-imaged diffraction coupled model in a Talbot cavity for vertical cavity surface emitting laser arrays, the effect of self-imaged reflections on the lasing threshold of a finite 2-D array was investigated. Array size and the ratio defined by the element diameter/element spacing were found to affect the effective reflectivity as seen from the laser cavities and, ultimately, the device threshold. A general curve showing the dependence of the 2-D coupling coefficient on the array fill factor and array size has been found. Minimum levels of laser facet reflectivities have been obtained as a function of the array fill factor for practical devices with low threshold current densities.