QoQeliQo Project: next-generation visible lasers for quantum technologies

The QoQeliQo project aims to develop compact, coherent, and cost-competitive visible lasers to accelerate the industrialization of quantum technologies.

The QoQeliQo project officially kicked off on October 10, 2024. It aims to bring to the industrial stage competitively priced, compact visible lasers that meet the demanding needs of the quantum sector.

By doing so, QoQeliQo provides the community with a new technological building block combining high power and ultra-narrow linewidth.

Mid-Project Progress Update

We have now reached the midpoint of the project and recently presented our latest results to the project funders. A 532 nm laser has been delivered to Silentsys to start integration into the QoQeliQo prototype. On the Oxxius pump laser, we demonstrated an integrated linewidth of 3.8 kHz (10 ms integration time) and an intrinsic linewidth of ~30 Hz, representing a major step beyond the initial target of 1 kHz intrinsic linewidth.

In parallel, a second 532 nm laser and a new 556 nm laser are ready for testing at Institut FOTON. We also demonstrated frequency tunability of the 532 nm DPSS laser over several GHz, including fast tuning over several tens of MHz, supporting integration needs and advanced control schemes.

Finally, the proof of concept (POC) using an integrated Oxxius 532 nm pump laser delivered very strong system-level results: acoustic noise of 23 dB, and excellent Brillouin laser performance for the QoQeliQo source, with an integrated linewidth of 1.4 kHz (10 ms), an intrinsic linewidth of approximately 1 Hz and an output power of around 30 mW.

Quantum Challenges and Requirements

Quantum applications—such as atomic clocks, quantum computing, atomic and molecular spectroscopy, and quantum sensors—demand lasers with ultra-high spectral purity and sub-kHz linewidths.
Many critical atomic transitions lie in the visible spectrum. In particular, strontium and ytterbium are strong candidates for large-scale deployment in quantum devices.
Today’s commercially available lasers often exhibit intrinsic linewidths in the tens of kHz, which remain insufficient for the most advanced requirements.

Our Approach

QoQeliQo introduces a breakthrough in visible laser performance by applying Stimulated Brillouin Scattering (SBS) to narrow the linewidth of a frequency-tunable pump laser:

At least 100× linewidth reduction compared to current sources.
First-ever industrial implementation of SBS in the visible range, a technique previously demonstrated in the infrared.
Watt-level optical power while maintaining exceptional coherence.
A platform technology: applicable to any wavelength, provided a suitable monochromatic pump source and advanced fiber components are available.

Consortium & Expertise

Institut Foton – Develops Brillouin lasers and validates the spectral-narrowing module across multiple wavelengths.
SILENTSYS – Designs the electronics, ensures robust system integration and packaging, and drives early market introduction.
Oxxius – Contributes with:

— Fast frequency modulation on DPSS lasers,

— Development of new single-frequency sources (DPSS and diode),

— Power scaling of DPSS lasers.