Silicon-on-Insulator-Based Broadband 1$\times$3 Adiabatic Splitter with Simultaneous Tapering of Velocity and Coupling

We propose and experimentally demonstrate a broadband $1\times3$ adiabatic splitter based on the silicon-on-insulator technology, with simultaneous tapering of velocity and coupling. The designed structure becomes simulated transmission uniformity of three outputs better than 0.5 dB in a broadband of 250 nm, and a large simulated fabrication tolerance is obtained. A manufactured splitter whose parameters greatly diverge from the design acquires a measured result of the worst splitting ratio better than 1.5 dB as well as an excess loss lower than 0.8 dB in a large wavelength range of 80 nm. A post-simulation based on the tested splitter obtains a result that meets the actual transmission well.