Physics

Optics

Radiation

Phased-array optics

Antenna (radio)

Materials science

Waveguide

Grating

Computer science

Apodization

Optoelectronics

Phased array

Telecommunications

Optics Express

Two novel waveguide gratings for optical phased array transmitters are investigated. By offsetting the grating structures along the waveguide on the upper and lower surfaces of the silicon nitride (Si 3 N 4 ) waveguide, the dual-level chain and dual-level fishbone structures can achieve 95% of unidirectional radiation with a single Si 3 N 4 layer by design. With apodized perturbation along the gratings, both structures can achieve uniform radiation without compromising the unidirectional radiation performance. In experiment, both demonstrate ∼ 80-90% unidirectionality. With further analysis, it is found that the dual-level fishbone structure is more feasible and robust to process variations in uniform radiation.

Unidirectional large-scale waveguide grating with uniform radiation for optical phased array