Broadband silicon nitride arbitrary ratio power splitters

We design a type of broadband Silicon Nitride (SiN) power splitters with various split ratios using shortcuts to adiabaticity (STA) technique to ensure the compactness and performance of the device. The decoupled system states are employed in the double-waveguides system to guarantee the approximate adiabatic evolution and the desired split ratios are implemented by manipulating the boundary conditions. The devices show broadband response for a wide wavelength range from 1260 to 1360 nm and have excellent robustness against fabrication errors in our simulations.