AN INVESTIGATION OF THE MODAL COUPLING OF SIMPLE BRANCHING SEMICONDUCTOR RING LASERS

We have investigated, by simulation, the coupling efficiencies of a ri ng laser into a straight guide in terms of the power splitting ratio b etween the fundamental modes of the ring and straight output guide, as well as the proportion of power lost to higher-order excitations of t he straight guide. The results show that the typical design for a bran ching ring laser can be optimized by offsetting the output guide posit ion and choosing the proper guide width. This analysis also shows that the symmetrical dual output port design (i.e., tangential straight gu ide) can result in very poor output coupling efficiencies as compared to the single output port design.