MOde LOcKing for Advanced Sensing and Imaging)

Introduction

The optical frequency comb is a spectrum of evenly spaced narrow laser lines. Optical frequency combs have revolutionized time and frequency metrology by linking microwave and optical frequencies. However, realizing their full potential in a broader range of applications such as 3D imaging, environmental sensing, LIDAR, and high-speed optical communications, is conditioned by the availability of inexpensive highly miniaturized devices.

Progress in Integrated Optics

Progress in integrated optics towards chip-scale frequency combs has made significant strides in recent years. UGent has been at the forefront of this evolution. It has developed unique technologies in heterogeneous integration, enabling the long-missing functionality of optical gain on a chip.

This unlocks the full integration of combs, in particular, in the infrared, but also in the near-infrared range (800-1100 nm). This range is key to sensing in water-dominated media as encountered in biological samples, e.g., in optical coherence tomography settings, food industry, and environmental sensing.

Collaboration in MOLOKAI

In MOLOKAI, UGent will engage in a close collaboration with the group at MBI, which is the pioneer of the applications of frequency combs applied to dual-comb interferometry. In particular, MBI is the initiator of the extension of frequency-comb techniques to:

1. 3D imaging
2. Raman spectroscopy

In this way, in MOLOKAI, we aim to leverage the latest breakthroughs in chip-scale frequency-comb technology to transition these technologies into a real-life setting.

Development of Broadband On-Chip Interferometer

MOLOKAI will work further on our initial dual-comb results to make a broadband on-chip interferometer. For that, MOLOKAI will collaborate closely with IBSEN Photonics, a spectrometer company, to make high-resolution spectrometers that can be used to read out Bragg sensors in fibers.

Future Prospects

Next, the dual-comb technology will be ported to a GaAs-on-silicon nitride platform. Here, dual-comb systems allow for the prospect of high-resolution images.