Wide-Angle Beam-Steering Using an Optical Phased Array with Non-Uniform-Width Waveguide Radiators

Youngin Kim,Hyeonho Yoon,Jong-Bum You,Hyo-Hoon Park,Minchul Kim

doi:10.3390/photonics7030056

Youngin Kim, Hyeonho Yoon + Show 3 more

Open Access

https://doi.org/10.3390/photonics7030056

Copy DOI

Abstract

We demonstrate wide-angle beam-steering using an optical phased array (OPA) with waveguide radiators designed with non-uniform widths to reduce the crosstalk between waveguides. The OPA consists of a silicon based 1 × 16 array of electro-optic phase shifters and end-fire radiators. The 16 radiators were configured with four different widths and a half-wavelength spacing, which can remove the higher-order diffraction patterns in free space. The waveguides showed a low crosstalk of −10.2 dB at a wavelength of 1540 nm. With phase control, the OPA achieved wide beam-steering of over ±80° with a side-lobe suppression of 7.4 dB.

Highlights

Optical phased arrays (OPAs) based on silicon photonics are promising for three-dimensional imaging applications because of their compactness, fast scanning speed and low power consumption [1,2]
These structures, disperse the radiation power to the side-lobes, resulting in a reduction in the side-lobe suppression ratio. Another route to forming a single beam is to narrow the pitch of the radiators to within a half-wavelength space, at which the higher-order diffraction peaks disappear in the free space [9]
We demonstrate a silicon-based 1 × 16 OPA using end-fire radiators with a non-uniform-width waveguide array and p-i-n electro-optic (EO) phase shifter

Summary

Introduction

Optical phased arrays (OPAs) based on silicon photonics are promising for three-dimensional imaging applications because of their compactness, fast scanning speed and low power consumption [1,2]. One of the important requirements for this application is an assured wide beam-steering of a zeroth-order beam, while avoiding an appearance of higher-order diffraction beams. To satisfy this requirement, various methods which can suppress the higher-order grating lobes and side-lobes have been proposed [3,4,5,6,7,8]. Spaced radiator arrays have been employed as the structures which suppress the high-order grating lobes [3,4,5] These structures, disperse the radiation power to the side-lobes, resulting in a reduction in the side-lobe suppression ratio. Another route to forming a single beam is to narrow the pitch of the radiators to within a half-wavelength space, at which the higher-order diffraction peaks disappear in the free space [9]

Methods

Discussion

Conclusion