Design and Characterization of a Top Cladding for Silicon-on-Insulator Grating Coupler

An effective top cladding for silicon-on-insulator grating coupler is designed and the validity of the design is confirmed experimentally. The proposed double-layer silicon oxide/silicon nitride (SiO₂/Si₃N₄) cladding demonstrates antireflection properties and affects a coupling strength of the grating structure. A coupling efficiency of 65% is obtained after cladding layer deposition.