Non-periodic high-index contrast gratings reflector with large-angle beam forming ability

• A non-periodic high-index contrast gratings (HCGs) reflector on SOI wafer with a large deflecting angle of 20° has been proposed and fabricated.
• A deflecting angle of 17.35° and high reflectivity of 92.31% are achieved by simulation.
• Experimental results show that the reflected powers of the proposed non-periodic HCGs reflector all peaked at 17.2° in a wavelength range as wide as 40 nm around 1550 nm.

A non-periodic high-index contrast gratings (HCGs) reflector on SOI wafer with large-angle beam forming ability has been proposed and fabricated. The proposed reflector was designed using rigorous coupled-wave analysis (RCWA) and finite-element-method (FEM). A deflection angle of 17.35° and high reflectivity of 92.31% are achieved under transverse magnetic (TM) polarized light in numerical simulation. Experimental results show that the reflected power peaked at 17.2° under a 1550 nm incident light, which is in good accordance with the simulation results. Moreover, the reflected power spectrum was also measured. Under different incident wavelengths around 1550 nm, reflected powers all peaked at 17.2°. The results show that the proposed non-periodic HCGs reflector has a good reflection and beam forming ability in a wavelength range as wide as 40 nm around 1550 nm.