Controlling On-chip Optical Radiation with All-Dielectric Antennas: Reconfigurable Interconnects and Lab-on-a-chip Devices

Introduction Photonic integrated circuits (PICs) promise to open new avenues in high-performance computing, biosensing or optical beamforming, amongst others. Current PICs rely on the use of guided interconnects, hampering... [ view full abstract ]

Introduction

Photonic integrated circuits (PICs) promise to open new avenues in high-performance computing, biosensing or optical beamforming, amongst others. Current PICs rely on the use of guided interconnects, hampering the creation of flexible and reconfigurable networks-on-a-chip and preventing the far-field light-matter interaction required for many sensing applications. In this work, we propose¹ a novel on-chip silicon antenna that, in contrast to their plasmonic counterparts², exhibits simultaneously an ultra-high directivity (>100), low loss, low reflections and a broadband response (Fig. 1). We propose the use of these nanoantennas as the main building blocks of a new wireless photonic platform that solves the aforementioned problems and considerably widens the range of achievable integrated photonic functionalities.  

Methods

The studied antennas consist of inverted-taper silicon strips with additional structures behaving as directors, and were modelled via Huygens’ Principle in combination with full-wave simulations (Fig. 1). The antennas were fabricated over silicon-on-insulator wafers using standard e-beam fabrication processes, assuring CMOS compatibility.

Results

As a first basic application, we demonstrated the first on-chip wireless data-streaming link, with a speed as high as 160 Gbit·s^-1 over a distance of 100 µm. Moreover, to illustrate the potential of these antennas for reconfigurable networks, we developed an electrically-controlled antenna-array beam-steering device, which allowed us to dynamically steer radiated beams by tuning the feeding waveguides phase (α) through silicon’s thermo-optic effect (Fig. 2). Finally, we built an ultra-compact (with a footprint several orders of magnitude smaller than previous versions) lab-on-a-chip antenna-based microflow cytometer able to classify microparticles of different size via their time-dependent scattered-field signature with state-of-the-art resolution (Fig. 3).

Discussion

These results demonstrate the potential offered by the proposed wireless platform, providing much more flexible optical interconnects and the ability of developing reconfigurable architectures, as well as boosting new applications in other fields such as the generation of complex beams for material processing or optical tweezing. From a lab-on-a-chip perspective, the proposed microflow cytometer paves the way to point-of-care biomedical equipment and interesting additional applications such as on-chip dynamic light scattering, Raman spectroscopy or gas chromatography.

• Light Sci App 2017; 6: e17053.
• Nat Photonics 2011; 5: 83-90.