No abstract

Data exchange among different mode channels is indispensable for optical communication system adopting modedivision multiplexing. Traditional mode exchange device is complex in procedure and large in footprint, which makes it not suitable for dense and large-scale photonic integration. Utilizing the degree of freedom of silicon meta-structure, we design an ultracompact and optically broadband mode exchange device between TE 0 and TE 1 modes by the step-by-step inverse-design method considering the axisymmetric constraint. Simulation result shows that it is robust to a temperature variation of 100 K and a fabrication error of ±20 nm. The fabricated device is 4 × 1.6 μm 2 in footprint. The simulated conversion efficiencies are over 73% and 71% for TE 0 to TE 1 and TE 1 to TE 0 within the whole C-band, and the experimental results are about 10% lower than the simulation. 40 Gbps OOK and 25 GBaud PAM-4 data transmission through the device are carried out, which shows good signal quality. We envision that the device will offer a flexible mode manipulation in optical interconnect system.