1×3 reconfigurable and simultaneous three-mode selective router based on silicon waveguide utilizing Ti microheaters as thermo-optic phase shifters

In this work, a photonic-silicon-based 1✕3 reconfigurable simultaneous three-mode selective router has been demonstrated by the proof-of-concept. The device can be flexibly controlled to route three input modes of TE0, TE1, and TE2 to three outputs by utilizing three controllable Ti thermo-optic phase shifters as drivers. The proposed router is constructed from a Ψ -junction coupler and two kinds of 3✕3 multi-mode interference (MMI) couplers. The proposed device can attain low insertion loss smaller than 5 dB and crosstalk below −20 dB in broadband of 40-nm thanks to the numerical simulation-based optimization. Furthermore, the proposed router has relatively large fabrication tolerances of width and height and consumes a low electric power consumption. The proposed device is reconfigurable for simultaneous three guided modes, and thus, leading to a promising potential to widely apply for broadband optical signal processing in the mode-division multiplexing systems.