Key Points
- Scientists developed a high-efficiency electro-optic frequency comb using lithium tantalate.
- The new material offers 17 times lower birefringence than lithium niobate, enhancing bandwidth.
- The device reduces microwave power consumption by nearly 20 times. It features a compact 1×1 cm² design and requires no complex tuning.
- The device achieves 450 nm spectral coverage with over 2,000 comb lines. Potential applications include telecommunications and robotics.
Scientists have achieved a major breakthrough in electro-optic frequency comb technology by developing a new device based on lithium tantalate. This device offers unprecedented bandwidth and energy efficiency. The research, conducted by teams from EPFL, the Colorado School of Mines, and the China Academy of Science, overcomes long-standing challenges in the field and has been published in Nature.
Frequency combs are essential in modern optics and are used for applications ranging from telecommunications to astrophysics. Traditional approaches, such as femtosecond lasers and Kerr soliton micro combs, have provided effective solutions, but they have complex tuning requirements and high power demands, limiting their practical deployment. Electro-optic frequency combs, first introduced in 1993, promised a more efficient solution but have struggled with bandwidth and energy consumption issues.
The new device leverages lithium tantalate, a material with 17 times lower intrinsic birefringence than lithium niobate, the traditional material used in such devices. This improvement significantly expands the comb’s bandwidth while drastically reducing microwave power requirements by nearly 20 times.
Led by Professor Tobias J. Kippenberg, the research team developed an “integrated triply resonant” architecture. This system harmonizes three interacting fields—two optical and one microwave—by embedding a distributed coplanar waveguide resonator on lithium tantalate photonic integrated circuits. As a result, the device achieves an impressive 450 nm spectral coverage with over 2,000 comb lines.
In addition to its high efficiency, the new comb generator features a compact design, fitting within a 1×1 cm² footprint. It operates with a simple, free-running distributed feedback laser diode, making it significantly easier to use than conventional Kerr soliton-based devices that require intricate tuning.
With its enhanced performance, stability, and user-friendly design, the new device has the potential to revolutionize fields such as robotics, environmental monitoring, and precision sensing. The success of this co-design approach also underscores the exciting possibilities of integrating microwave and photonic engineering for next-generation technologies.
