ADVERTORIAL
SPECTRAL PURITY TRANSFER
Enabling Ultimate Stability at Every Wavelength with Menlo Systems’ Frequency Comb Technology.
Optical frequency combs( OFCs) are essential in applications including optical clocks, spectroscopy, quantum technologies, and astronomical spectrograph calibration. Many of these applications require frequency references at wavelengths where the most stable lasers are not readily available, making broad and accurate access to optical frequencies essential.
OFCs are typically generated by modelocked lasers, which produce ultrashort pulses in the time domain. In the frequency domain, these pulses correspond to a series of equally spaced, discrete spectral lines, similar to the teeth of a comb( hence the name). If the comb’ s repetition rate, f rep, and carrier-envelope offset frequency, f ceo, are known, all frequencies of the comb can be determined.
For high-precision applications, however, generating a broad comb spectrum is only part of the challenge. The spectral purity of an ultrastable optical reference must also be preserved over the whole comb spectrum.
This can be achieved by optically locking the comb to a continuous-wave reference laser. A beat note between the reference laser and a comb tooth is detected and used to stabilize the comb. However, controlling only f rep does not provide complete control of the comb spectrum. Independent control of both f rep and f ceo is essential for low-noise transfer across the comb spectrum. Menlo Systems’ dual-actuation approach combines precise repetition-rate control with active f ceo stabilization. This suppresses offset-frequency noise and reduces phase noise on comb teeth, even when they are spectrally far removed from the optical reference, enabling highly stable and coherent frequency transfer. This spectral purity is preserved even throughout frequency-conversion processes such as frequency shifting, second-harmonic generation, and supercontinuum generation.
▲( a) Free-running optical frequency comb.( b) Locking an optical frequency comb to an external optical reference via a conventional repetition rate control loop: Linewidth and phase noise increase with spectral distance from the reference.( c) Complementing the repetition rate lock by f ceo-control replicates the spectral purity of the external optical reference across every single comb line.
For more than 25 years, Menlo Systems has served the optical community with high-end optical frequency combs and fully integrated commercial solutions for applications including precision timekeeping, quantum computing, spectrograph calibration, and more.
The SmartComb-ULN brings Menlo Systems’ ultra-low-noise frequency-comb technology into a compact, robust, and fully automated turnkey platform. Designed for demanding precision applications, it combines high-end comb performance with a compact form factor and broad spectral access, supporting applications across the visible, near-infrared, and infrared spectral ranges. Its robust technology is suited to both stationary and mobile applications, including demanding environments.
Currently, Menlo Systems’ ultra-lownoise optical frequency combs are key enablers for quantum computing development, such as the Munich Quantum Valley project‘ MUNIQC- Atoms’ [ 1 ]; optical clock development for various transitions, from strontium and rubidium to iodine; and real-world deployment, with multiple projects using combs aboard spacecraft. Finally, Menlo OFCs are deployed in a range of astronomical observatories around the globe, demonstrating their role in transferring highly stable optical frequencies from one wavelength to another, and from the laboratory to the outside world.
REFERENCE
[ 1 ] MUNIQC-Atoms, Available: https:// muniqc-atoms. munichquantum-valley. de / about( accessed September 2026)
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