Silicon-on-insulator-based adiabatic splitter with simultaneous tapering of velocity and coupling.

We propose and experimentally demonstrate a 2×2 3 dB adiabatic splitter based on silicon-on-insulator technology, with simultaneous tapering of the phase velocity and coupling. The advantages of the proposed splitter are indicated by analyzing the effective index evolution of the system modes and comparing them with the simulated performances. The experimental results are in good agreement with the simulations. Over the 100 nm wavelength range measured, the output uniformity is better than 0.2 dB. A low and flat excess loss of about 0.3 dB per splitter is obtained, with a variation below 0.2 dB.