TY - JOUR

T1 - On the performance of optical phased array technology for beam steering: effect of pixel limitations

AU - Calà Lesina, Antonino

AU - Goodwill, Dominic

AU - Bernier, Eric

AU - Ramunno, Lora

AU - Berini, Pierre

N1 - Funding Information: We acknowledge computational support from SciNet and Compute Canada, and financial support from NSERC and Huawei Technologies Canada. A.C.L. acknowledges the Bundesministerium für Buldung und Furschung (German Federal Ministry of Education and Research) under the Tenure-Track Programme, and the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under Germany’s Excellence Strategy within the Cluster of Excellence PhoenixD (EXC 2122, Project ID 390833453). The publication of this article was funded by the Open Access Fund of the Leibniz Universität Hannover.

PY - 2020/10/12

Y1 - 2020/10/12

N2 - Optical phased arrays are of strong interest for beam steering in telecom and LIDAR applications. A phased array ideally requires that the field produced by each element in the array (a pixel) is fully controllable in phase and amplitude (ideally constant). This is needed to realize a phase gradient along a direction in the array, and thus beam steering in that direction. In practice, grating lobes appear if the pixel size is not sub-wavelength, which is an issue for many optical technologies. Furthermore, the phase performance of an optical pixel may not span the required 2π phase range or may not produce a constant amplitude over its phase range. These limitations result in imperfections in the phase gradient, which in turn introduce undesirable secondary lobes. We discuss the effects of non-ideal pixels on beam formation, in a general and technology-agnostic manner. By examining the strength of secondary lobes with respect to the main lobe, we quantify beam steering quality and make recommendations on the pixel performance required for beam steering within prescribed specifications. By applying appropriate compensation strategies, we show that it is possible to realize high-quality beam steering even when the pixel performance is non-ideal, with intensity of the secondary lobes two orders of magnitude smaller than the main lobe.

AB - Optical phased arrays are of strong interest for beam steering in telecom and LIDAR applications. A phased array ideally requires that the field produced by each element in the array (a pixel) is fully controllable in phase and amplitude (ideally constant). This is needed to realize a phase gradient along a direction in the array, and thus beam steering in that direction. In practice, grating lobes appear if the pixel size is not sub-wavelength, which is an issue for many optical technologies. Furthermore, the phase performance of an optical pixel may not span the required 2π phase range or may not produce a constant amplitude over its phase range. These limitations result in imperfections in the phase gradient, which in turn introduce undesirable secondary lobes. We discuss the effects of non-ideal pixels on beam formation, in a general and technology-agnostic manner. By examining the strength of secondary lobes with respect to the main lobe, we quantify beam steering quality and make recommendations on the pixel performance required for beam steering within prescribed specifications. By applying appropriate compensation strategies, we show that it is possible to realize high-quality beam steering even when the pixel performance is non-ideal, with intensity of the secondary lobes two orders of magnitude smaller than the main lobe.

KW - eess.SP

KW - physics.optics

UR - http://www.scopus.com/inward/record.url?scp=85093921769&partnerID=8YFLogxK

U2 - 10.1364/OE.402894

DO - 10.1364/OE.402894

M3 - Article

VL - 28

SP - 31637

EP - 31657

JO - Optics Express

JF - Optics Express

SN - 1094-4087

IS - 21

ER -