Optical Mode Interleaver Based on the Asymmetric Multimode Y Junction

An optical mode interleaver (OMIL) based on the asymmetric multimode Y junction is proposed for realizing flexible selection of group of modes in mode-division multiplexing optical network. The odd and even modes of the stem can be sorted by carefully controlling the widths of the narrow and wide arms according to the constraint conditions of the propagation constants. A four-mode OMIL is analyzed as an example using the beam propagation method. The device is able to realize a low excess loss of <0.13 dB, a high mode extinction ratio that exceeded 28.4 dB, and a mode crosstalk lower than −25.5 dB over a common spectral bandwidth of 210 nm.