Design of Three-mode Multi/Demultiplexer Based on 2-D Photonic Crystals for Mode-Division Multiplexing Transmission

A three mode division multiplexer and demultiplexer (MMUX/DEMMUX) base on 2-D photonic crystal at 1550 nm was designed. Two asymmetrical directional couplers are included in this MMUX/DEMMUX, which can achieve modes conversion function of TE₀, TE₁ and TE₂ modes. In order to avoid phase mismatching in bus waveguide, taper directional is applied at waveguide junction which can reduce the insertion loss effectively. Plane waves method (PWM) and finite difference time domain (FDTD) methods were used to simulating the performance of MMUX/DEMMUX. Numerical simulations show that the designed device has the potential for high-capacity MDM optical communication systems with a low insertion loss (<0.27dB) and a low mode crosstalk (< −25.4 dB). (paper)