Numerical and experimental studies of the structural effect in symmetric PFA Y-junctions

The authors present a numerical analysis of the structural effect of single-mode symmetric Y-junctions using a phase front accelerator (PFA) and other low-loss wide-angle designs. The beam propagation method (BPM) was used for the numerical simulation. The authors show how the structural effect can reduce the transmission loss significantly with various PFA parameters. The transmission loss is then compared with those in similar designs investigated by Weissman et al. (1989) and Rangaraj et al. (1989). The authors analyze and compare the reduction of transmission loss in Y-junctions using the structural effect, truncated normal and truncated structural design. For half-branching angles larger than 1°, the proposed truncated structural design will offer lower transmission loss