On‐Chip Metamaterial Antenna Array with Distributed Bragg Deflector for Generation of Collimated Steerable Beams. Issue 9 (3rd July 2022)

• Record Type: Journal Article
• Authors: Ginel‐Moreno, Pablo; Hadij‐ElHouati, Abdelfettah; Sánchez‐Postigo, Alejandro; Wangüemert‐Pérez, J. Gonzalo; Molina‐Fernández, Íñigo; Schmid, Jens H.; Cheben, Pavel; Ortega‐Moñux, Alejandro
• Is Part Of: Laser & photonics reviews. Volume 16:Issue 9(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-07-03
• Subjects: Bragg structures -- Fourier optics -- optical antennas -- optical phased arrays -- silicon photonics -- subwavelength grating metamaterials; Lasers -- Periodicals; Photonics -- Periodicals; Lasers -- Périodiques; Photonique -- Périodiques; 621.36
• DOI: 10.1002/lpor.202200164
• Languages: English
• ISSNs: 1863-8880

Abstract

Abstract: The generation of collimated steerable beams of light is a fundamental function in optics needed in many applications, including free‐space optical communications, remote sensing, and light detection and ranging. Implementing large‐aperture light emitters directly on a photonic integrated chip without using external optics and expensive alignment systems is an outstanding challenge in integrated photonics. Here, the experimental demonstration of a new integrated antenna array architecture that uses a compact feeding circuit is reported. The design is based on an apodized Bragg deflector working as a low‐loss (<0.3 dB) ultra‐compact beam expander, which generates a 40‐µm‐wide on‐chip Gaussian beam that illuminates a one‐dimensional array of 112 optical antennas with a length of 1.5 mm. Each antenna comprises a metamaterial subwavelength grating waveguide core that is laterally loaded with an array of periodic radiative silicon segments. The device is fabricated on a 220‐nm silicon‐on‐insulator platform using a single etch process with a minimum feature size of 80 nm. An antenna array with a power gain of 50 dB, a radiation efficiency of −3.8 dB, and a far‐field angular divergence of 1.8° × 0.2°, in a wavelength range of 1500–1580 nm is presented. Abstract : A novel feeding architecture for optical phased arrays that is based on a distributed Bragg deflector (DBD) is experimentally demonstrated. The DBD acts as a beam expander that illuminates 112 surface‐emitting metamaterial antennas. This scheme allows to obtain a highly collimated steerable beam in the far‐field and can be easily adapted to feed arrays with an increased number of antennas.