Design and Fabrication of Broadband PLC-Based Two-Mode Multi/Demultiplexer Using a Wavefront Matching Method

A broadband and low-loss two-mode (LP01/LP11a) multi/demultiplexer (MUX/DEMUX) based on a planar lightwave circuit (PLC) is designed by a wavefront matching method, which is an optimization algorithm of PLC based on the beam propagation method. The calculated transmission loss of the optimized structure is lower than -0.3 dB in the wavelength range from 1400 to 1700 nm. Numerical results show that the proposed structure has large fabrication tolerance compared to the conventional structure. The designed structure is fabricated and broadband characteristics are well-reproduced, showing the usefulness of the proposed MUX/DEMUX.