EPFL researchers have demonstrated an ultrafast laser on a chip that could replace some of the largest laboratory systems in measurements, sensing, and spectroscopy in the future.
Ultrafast lasers are important tools in science and technology. They produce extremely short pulses, on the order of femtoseconds, and are used, among other things, in measuring fast processes, spectroscopy, atomic clocks, materials processing, and medical applications. The problem is that such systems are often large, expensive, and complex to operate. A new study by EPFL researchers, published in Nature, presents a way to reduce some of these capabilities to a photonic chip. (Nature)
The researchers demonstrated a combined mode-locked laser based on a silicon nitride chip with erbium ions implanted. According to the paper, the laser produces a pulse train at 176 MHz, with pulse energy in the nanojoule range, and the pulses can be compressed to 147 femtoseconds. This data is important because previous combined photon sources have struggled to provide sufficient pulse energy for nonlinear processes, such as supercontinuum generation.
Not just miniaturization
The obvious title is “Laser on a Chip,” but it’s not just about size. In ultrafast lasers, the key question is not just whether short pulses can be produced, but whether they are powerful, stable, and coherent enough to drive real-world applications. Nature reports that the new system produces pulse energy that is more than two orders of magnitude greater than previous integrated photon sources, approaching the performance of larger fiber lasers.
The system is based on an architecture known as a Mamyshev oscillator. Rather than explaining it as “optical magic,” it is more accurate to describe it as a filtering and control mechanism: the light undergoes spectral broadening in a nonlinear medium, after which optical filters allow only a portion of the light to continue circulating in the laser cavity. In this way, strong pulses are preserved and shaped, while weaker components are filtered out.
Chip instead of optical table
According to an EPFL announcement, the chip introduces a laser architecture that was previously limited to larger systems, shrinking it to the scale of millimeters. In an image released by the university, the chip is seen placed on a one Swiss franc coin to illustrate the scale.
The possible implication is a gradual transition from large, complex optical systems to components manufactured using chip technologies. Such production may enable more compact, more stable, and cheaper devices in the future, if the development matures for large-scale production. It is important to be careful here: the research presents an advanced scientific demonstration, not an immediate commercial product.
What can be done with such pulses?
In a paper in Nature, the researchers report that the laser was able to directly drive the formation of a supercontinuum in a silicon nitride waveguide, without further amplification. Supercontinuum is a broad-spectrum light created by nonlinear processes, and is useful for measurements, spectroscopy, metrology, and other applications.
The researchers also demonstrated a compact terahertz spectrometer powered by the new source, with a bandwidth of 5 terahertz and a dynamic range of 90 decibels. According to Nature, the system was used to demonstrate non-contact chemical analysis and materials testing. These are still research demonstrations, but they show that pulses are not just a pretty number, but can drive an entire measurement system.
Importance of chips and integrated photonics
The development fits into a broader trend: moving optical components that were previously external, large, and highly precise to photonic chips. Like electronic chips, photonic chips can be built on chip wafers, combining several functions on the same component, and connecting to other systems. If ultrafast lasers can be integrated in this way, they could expand the use of advanced measurement tools outside of dedicated laboratories.
For CHIPORTAL, the central angle is integrated photonics and the fabrication of optical components at the chip scale. For the scientist, the broader angle is measurement science: smaller tools to measure fast processes, identify materials, improve spectroscopy, and develop portable sensing systems. In both cases, the correct formulation is not “an instant revolution,” but an important step in the miniaturization of advanced optical technology.
for the scientific articlehttps://www.nature.com/articles/s41586-026-10517-4
Short FAQ:
What is a femtosecond laser? A laser that produces extremely short pulses, on the order of a quadrillionth of a second.
What's new in EPFL's research? The researchers were able to integrate a photonic source on a chip that produces short, high-energy pulses relative to previous integrated systems.
Is this a commercial product? No. This is a research demonstration, but it points the way to more compact applications in the future.
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