Frequency comb paves the way for compact high-precision photonics

Researchers from EPFL, the Colorado School of Mines and the China Academy of Science have developed an ultra-broadband electro-optic frequency comb that achieves a spectacular spectral coverage of 450 nm. The lithium tantalate-based chip requires 20 times less power than previous designs and could herald a new era of miniaturisation and efficiency in photonics.

Frequency combs are essential tools in modern optics. They enable high-precision measurements and are used in telecommunications, environmental monitoring and even astrophysics. Until now, however, compact, energy-efficient solutions have been difficult to realise.

The new electro-optical comb generator design developed by an international research team is revolutionising this technology. With more than 2000 comb lines on an area of just 1 cm², it offers unrivalled precision and compactness.

Lithium tantalate as a key component
At the centre of the development is lithium tantalate (LTO), a material that has 17 times less birefringence than lithium niobate. This property reduces interference between light waves, which enables uniform and stable comb generation.

By combining microwave and optical circuits on a single platform, the team was able to develop an integrated triple resonant architecture in which three fields – two optical and one microwave – resonate harmoniously.

Energy efficiency and versatility
A decisive advance is the significantly reduced energy requirement: the new design requires almost 20 times less microwave power than previous models. In addition, the compact design enables practical integration into photonic systems that previously relied on bulky and energy-intensive solutions.

Potential applications in high-tech industries

• Robotics: high-precision laser measurements for autonomous systems
• Spectroscopy and sensor technology: Accurate gas detection and environmental analyses
• Telecommunications: more efficient optical networks with lower energy consumption

A milestone for photonics
The new design demonstrates the potential of co-integrating microwave and photonic technology for future applications. By combining high precision, low energy consumption and compact design, this development could represent a turning point for optical technologies.