New nanopatterning flexible topology for on-chip photonic metamaterials

By periodically patterning waveguides at the subwavelength scale, a wide range of equivalent refractive indexes can be synthesized lithographically on a chip. What is more, with the ability to also engineer dispersion and anisotropy, these metamaterials are enabling completely new design strategies yielding devices with unprecedented performance, including ultra-broadband nanophotonic components, metalenses, polarization management devices or high sensitivity waveguide sensors. However, to avoid Bragg resonances, subwavelength grating metamaterials often require fabrication resolutions of 100 nm and below at telecom wavelengths. While narrow single-mode subwavelength waveguides can operate with larger periods, for more sophisticated devices implemented in planar waveguides, the required resolutions can be prohibitively small to be fabricated with wafer-scale lithography techniques. Therefore, exploiting the full potential of subwavelength metamaterials is challenging with current wafer-scale fabrication technologies, jeopardizing the broad use of high-performance metamaterial designs in silicon photonic devices.

To overcome this limitation, researchers from the Photonics & RF Research Lab group of the University of Málaga propose a new topology of nanostructured waveguide: the bricked subwavelength grating waveguide, capable of synthetizing artificial anisotropic homogeneous materials with lithographic control over anisotropy and dispersion, while allowing larger minimum feature sizes. The new pattern only needs one single etch step and makes use of a Manhattan-like geometry, with a uniform grid and pixel dimensions as large as 150×150 nm2 for telecom wavelengths, thereby paving the way towards wafer-scale fabrication. The control over the metamaterial optical properties enabled by bricked subwavelength grating waveguide opens new avenues for designing silicon photonics integrated circuits with exceptional performance and high fabrication yield.

The represented institution is looking for a collaboration that leads to commercial exploitation of the presented invention.

Institution: Universidad de Málaga

TRL: 5-6

Protection status: Patent Application

Contact: Laura Núñez /