Reconfigurable parallel-demultiplexing-sorter with low-loss and dynamic phase control for scalable multimode photonic network-on-chips

For mode-division multiplexing (MDM)-based photonic network-on-chips (NoCs), the conventional demultiplexing-processing-multiplexing architecture is prone to introducing excess loss and crosstalk, resulting in unbalanced performance and large size. The rigid framework severely limits signal processing flexibility and increases system complexity due to the reliance on two discrete steps. What we believe to be a novel N -mode reconfigurable parallel-demultiplexing-sorter (RPDS) integrating one symmetric N -junction, three N × N multimode interference (MMI) couplers, and 3⌊ N /2⌋ metal-heater phase shifters is demonstrated to combine demultiplexing and sorting in a single step. Dynamic phase control is achieved via the metal heaters, supporting reconfigurable full N ! signal-sorting permutations. Specifically, a tri-mode prototype of the proposed RPDS is fabricated on a silica-on-silicon platform. At the operating wavelength of 1550 nm, the prepared tri-mode RPDS exhibits a low insertion loss (IL) of 5.1 dB ± 1.1 dB across all six sorting configurations. Its 3-dB bandwidth spans 1510∼1560 nm, which is in good agreement with theoretical expectations. This flexible signal demultiplexing and sorting scheme overcomes the limitations of conventional architecture, boosts MDM system efficiency, and lowers complexity, thereby establishing a basis for scalable, high-efficiency multimode photonic applications. It enables promising deployments in 5G/6G communications, multi-user detection, radar signal sorting, electronic counter-countermeasures, and other application scenarios.