Circular Optical Phased Array with Large Steering Range and High Resolution

• Published in: Sensors (Basel, Switzerland) Vol. 22; no. 16; p. 6135
• Main Authors: Benedikovič, Daniel, Liu, Qiankun, Sánchez-Postigo, Alejandro, Atieh, Ahmad, Smy, Tom, Cheben, Pavel, Ye, Winnie N.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-08-2022; MDPI
• Subjects: Antennas; Arrays; beam forming; Beam steering; Broadband; Design; field-of-view; High resolution; optical antenna; optical phased arrays; Optical radar; Phased arrays; Photonics; Power; Radiation; Semiconductors; Sidelobe reduction; Sidelobes; Silicon; silicon photonics; Topology
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s22166135

Light detection and ranging systems based on optical phased arrays and integrated silicon photonics have sparked a surge of applications over the recent years. This includes applications in sensing, free-space communications, or autonomous vehicles, to name a few. Herein, we report a design of two-dimensional optical phased arrays, which are arranged in a grid of concentric rings. We numerically investigate two designs composed of 110 and 820 elements, respectively. Both single-wavelength (1550 nm) and broadband multi-wavelength (1535 nm to 1565 nm) operations are studied. The proposed phased arrays enable free-space beam steering, offering improved performance with narrow beam divergences of only 0.5° and 0.22° for the 110-element and 820-element arrays, respectively, with a main-to-sidelobe suppression ratio higher than 10 dB. The circular array topology also allows large element spacing far beyond the sub-wavelength-scaled limits that are present in one-dimensional linear or two-dimensional rectangular arrays. Under a single-wavelength operation, a solid-angle steering between 0.21π sr and 0.51π sr is obtained for 110- and 820-element arrays, respectively, while the beam steering spans the range of 0.24π sr and 0.57π sr for a multi-wavelength operation. This work opens new opportunities for future optical phased arrays in on-chip photonic applications, in which fast, high-resolution, and broadband beam steering is necessary.