In this project the feasibility and proof of concept of a commercial chip-based optical frequency comb was realized.
Optical frequency combs are equally spaced laser lines that are currently used for metrology, precise calibration, spectroscopy and many other scientific fields. Commercially available frequency combs are fiber based, which limits them in getting a large enough spacing that could be optically detectable. As they are custom made systems, they tend to be expensive and only available to dedicated experiments and R&D labs.
In contrary to the fiber based frequency comb, chip-based optical frequency combs can be engineered at any given frequency between 10GHz and 1THz and in this way enable new applications.
The challenges of a proof of concept study was to build a small system with available off-the-shelf OEM components and show the generation of a chip-based frequency comb.
We succeeded in developing an optical frequency comb generated from an integrated silicon nitride resonator with an affordable laser system and achieved packaging of the silicon nitride resonator with optical fibers to connect it to the laser system and the detection system.
This study showed the advanced technology development of integrated silicon nitride, which is now commercialized by LIGENTEC a spin-out from EPFL's laboratory. Furthermore, an experiment that was so far only run with laboratory equipment on a research level was demonstrated to work with off-the-shelf equipment and further integration and packaging. Engineering effort is still needed to turn the system into a commercially viable product and new developments make this within reach.
Many applications and markets could benefit from this development. Specifically, the integration of a chip-based frequency comb will open new application areas in telecommunication and sensing. Photonic integration of a frequency comb will bring down costs and power consumption.
