Automated design and optimization scheme of optical antenna for silicon photonic integrated circuit

Abstract

Optical antennas are essential components for integrated photonic circuits (PICs) as they allow the effective coupling of light into/from free space with large optical aperture and therefore small divergence angle. Such a function is especially vital in sensing applications such as LIDAR and Doppler velocimetry where the interaction with free space objects is required. However, the design of a linear grating optical antenna is not a trivial task, as the radiation intensity and angle need to be optimized along the antenna length to achieve the desired radiation pattern. In this work, we proposed and realized an automated design scheme for silicon PIC antennas. Utilizing such a scheme, an optical antenna array with 128 μm by 500 μm optical aperture has been designed and fabricated with 0.18 μm fabrication technology. The antenna has been characterized for its divergence angle and radiation pattern. The obtained data match well with design parameters, showing the viability of such an automated design scheme.