Improved coupling efficiency in photonic crystal tapered cylindrical hollow waveguides

We present a two-dimensional simulation of lowloss photonic crystal (PhC) defect waveguides built from a III-V type semiconductor based system surrounded by elliptical air pillars. We demonstrate a remarkable reduction in propagation losses for the proposed waveguides compared with previous taper designs, by means of a suitable design of the waveguide end-facets and a slight change in the periodic pattern of holes, minimizing the impedance mismatch and thereby the residual reflectance at the waveguide ends without introducing any additional processing step.