Chip Scale Electrically Powered Optical Frequency Combs

Project Information

ELECTRIC

Grant agreement ID: 759483

DOI

10.3030/759483

Project closed

EC signature date 8 September 2017

Start date 1 February 2018

End date 31 July 2023

Funded under

• EXCELLENT SCIENCE - European Research Council (ERC)

Total cost

€ 1 391 250,00

EU contribution

€ 1 391 250,00

Coordinated by

UNIVERSITEIT GENT
Belgium

Periodic Reporting for period 4 - ELECTRIC (Chip Scale Electrically Powered Optical Frequency Combs)

Reporting period: 2022-08-01 to 2023-07-31

Summary of the context and overall objectives of the project

Optical frequency combs (OFC) are light sources characterized by a spectrum comprising millions of laser lines, evenly distributed in frequency. This uniform frequency spacing establishes a crucial connection between the radiofrequency (RF) and optical frequency bands within the electromagnetic spectrum. This characteristic has profoundly transformed the fields of frequency metrology and precision laser spectroscopy. Recently, their application scope has expanded to encompass numerous new applications. Among these, their distinctive features have been harnessed in precision distance measurement experiments, as well as demonstrations of optical waveform and microwave synthesis.
Moreover, experiments in "dual-comb spectroscopy" have showcased broadband Fourier Transform Infrared (FTIR) spectroscopy with unprecedented resolution, sensitivity, and acquisition speeds. However, many of these demonstrations have relied on bulky experimental setups, hindering widespread deployment.
Our aim is to develop frequency combs on optical chips that can be mass-produced using CMOS technology. Unlike current chip-scale Kerr comb-based solutions, they do not require powerful continuous-wave laser optical pumping and can feature narrower comb spacing. In our project, conducted in collaboration with numerous partners, we have shown the feasibility of this approach. Specifically, we have demonstrated the ability to conduct dual-comb measurements of gases. This indicates low losses with sufficient resolution to resolve gas absorption lines.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

We have successfully assembled a team of experts and acquired the necessary equipment to develop these combs. In Ghent, we have now established a critical mass of expertise in both the design and fabrication of these devices. Additionally, we have made investments in integrating lithium niobate into our devices. Currently, several team members are dedicated to this integration, primarily focusing on modulators and frequency converters.
These efforts have resulted in multiple bilateral projects with industry partners for further research. One notable project focuses on commercializing LIDAR technology using combs, while we've recently secured funding for an EIC transition grant (MOLOKAI), where we serve as the coordinator to advance the technology beyond the research phase.
Furthermore, we lead an EIC Pathfinder project (CSOC) investigating the potential use of mode-locked lasers in optical clocks. We've also initiated bilateral projects with several telecom and datacom giants to integrate lithium niobate into silicon photonics and silicon nitride photonics chips.
Lastly, through the Photonixfab JDK project, we are exploring methods to scale heterogeneous fabrication techniques for large-scale foundries such as X-Fab.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

As mentioned above, we have demonstrated the capability to mode-lock lasers with significant performance. This achievement was showcased in a highly demanding dual-comb spectroscopy application. Furthermore, these initial results are currently being scaled to the wafer level, marking the starting point of the transition grant Molokia. Additionally, we have proven our ability to integrate lithium niobate with devices. Although these devices are relatively large, making the transfer difficult, we have successfully shown feasibility. Our ongoing focus lies in scaling this integration to the wafer level. Through several bilateral projects with telecom and datacom companies, we aim to further showcase these capabilities.

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