Rigorous study of near and far fields for spot-size converted semiconductor lasers

Recently, monolithically integrated spot-size converters (SSCs) have increasingly been used to improve the butt-coupling efficiency between a single mode fiber and a semiconductor laser, without deteriorating the alignment tolerances. In this work, the simulated results presented show the expansion of the spot-size and consequently the increase in the coupling efficiency for various designs of spot-size converters. The reflection coefficients and a study of the alignment tolerances for such SSCs are also presented, as is the far field generated from the modal field profile of the lasers. A field expansion technique has been developed to estimate the evolution of the optical field near the laser facet