3-D electromagnetic modeling of polarization-dependent coupling characteristics of 1x3 linear array weakly fused fiber couplers

摘要

Based on the full-wave surface integral equations method and the steplike approximation technique, a three-dimensional (3-D) electromagnetic model for simulating polarization-dependent power-coupling behavior of 1 x 3 linear array weakly fused fiber couplers is proposed. The accuracy of the proposed numerical model is confirmed to be good by comparing with the measured power transfer behavior at the fusing and elongating process of the couplers. In the 3-D modeling view, the polarization-dependent coupling behavior of two practical couplers, 1/3 power splitter and wavelength-flattened coupler are numerically studied. It is seen that as the coupler is designed in a very weakly fused condition the polarization-dependent loss (PDL) is significantly increased. For designing the 1 x 3 coupler with low PDL, it is suggested that the aspect ratio has to be controlled in stronger fused range between 0.8 and 0.9. [References: 20]