Circular Optical Phased Array with Large Steering Range and High Resolution

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.This work was supported by the Natural Sciences and Engineering Research Council of Canada’s Collaborative R&D Grant Program by collaborating with Optiwave Systems, Inc., Slovak Grant Agency VEGA 1/0113/22, and Slovak Research and Development Agency under the project APVV-21-0217. Partial funding for open access charge: Universidad de Málag

High-speed operation of fiber-optic link impaired by wind gusts

The fast signal transmission is critical long-haul communication systems. They represent the key advancements, shaping information-communication technologies. Fiber-optic transmission suffers from many degradation effects, and of particular concern are stochastic fiber impairments represented by polarization mode dispersion (PMD). The PMD is critical as it limits link operation at data rates higher than 10 Gbps. In this work, we report on experimental measurements and theoretical analysis characterization for PMD-based propagation effects in optical fibers influenced by wind gusts. The study was performed on fiber-optic link that runs through 111-km-long optical power ground wire cables. Measured maximum of DGD was up to 10 ps for a wind speed of 20 m/s. This wind condition, the optical link maintained a reliable operation only for established 10 Gbps, while considerable link degradation was seen for data rates of between 40 and 100 Gbps