Grating Lobe-Free Silicon Optical Phased Array with Periodically Bending Modulation of Dense Antennas.

A grating lobe-free silicon optical phased array with large field of view is demonstrated. Antennas with periodically bending modulation are spaced at half wavelength or less. The experimental results show that the crosstalk between adjacent waveguides is negligible at 1550 nm wavelength. Additionally, to reduce the optical reflection caused by the sudden change of refractive index at the output antenna of the phased array, tapered antennas are added to the output end face so that more light will be coupled into the free space. The fabricated optical phased array shows a field of view of 120° without any grating lobes.