Waveguide Mode Splitter Based on Multi-mode Dielectric-Loaded Surface Plasmon Polariton Waveguide**Supported by the National Basic Research Program of China under Grant Nos 2011CBA00200 and 2011CB921200, the Strategic Priority Research Program (B) of the Chinese Academy of Sciences under Grant No XDB01030200, the National Natural Science Foundation of China under Grant No 11374289, the Fundamental Research Funds for the Central Universities

Abstract

In photonic integrated circuits, information is usually encoded in the optical path. In this work, based on the multi-mode dielectric-loaded surface plasmon polariton waveguide, we numerically design a directional coupler, which can divide the different waveguide eigenmodes into different optical paths. The results show a possibility to encode information onto different waveguide modes. We also experimentally demonstrate that the splitting ratio of this directional coupler structure can be tuned without changing its size.