Experimental demonstration of a silicon nanophotonic antenna for far-field broadened optical phased arrays

• DOI: 10.1364/prj.515222
• Publication Date: 2024-06-25T15:00:14Z
• Authors: Shahrzad Khajavi; Jianhao Zhang; Pavel Cheben; Daniele Melati; Jens H. Schmid; Ross Cheriton; Martin Vachon; Shurui Wang; Ahmad Atieh; Carlos Alonso Ramos; Winnie N. Ye
• Keywords: Beam steering; Nanophotonics

Optical antennas play a pivotal role in interfacing integrated photonic circuits with free-space systems. Designing for optical phased arrays ideally requires achieving compact antenna apertures, wide radiation angles, and high efficiency all at once, which presents significant challenge. Here, we experimentally demonstrate novel ultra-compact silicon grating antenna, utilizing subwavelength nanostructures arranged transversally interleaved topology to control the pattern. Through near-field phase engineering, increase antenna’s far-field beam width beyond Fraunhofer limit given aperture size. The incorporates single-etch Bragg reflector implemented on 300-nm-thick silicon-on-insulator (SOI) platform. Experimental characterizations of 44°×52° −3.22 dB diffraction efficiency, an size 3.4 μm ×1.78 . Furthermore, best our knowledge, 2D array is demonstrated first time, leveraging evanescently coupled architecture yield very array. We validated functionality design through its integration into this new topology. Specifically, small proof-of-concept two-dimensional 2×4 elements steering range 19.3º × 39.7º. A path towards scalability larger-scale also 8×20 transverse 31.4º.