Propagating-beam-method analysis of two-dimensional microlenses and three-dimensional taper structures

Abstract

We employ the propagating-beam method to determine the increase in coupling efficiency that is achievable if the end of a two-dimensional monomode taper is rounded before it is placed in front of a semiconductor laser. We find that the coupling efficiency in some cases can be augmented by more than a factor of 2. Subsequently, we describe some results that relate to three-dimensional taper structures and couplers built of two taper structures placed with their wide ends adjacent.