Researchers have achieved a milestone in integrated photonics by shrinking an ultrafast laser, once confined to large laboratory systems, onto a tiny photonic chip without sacrificing performance. The breakthrough addresses a challenge that scientists have pursued for more than two decades and could dramatically reduce the size, cost, and complexity of technologies used in medical diagnostics, precision manufacturing, spectroscopy, and advanced communications, tells Live Science.
Ultrafast lasers generate pulses lasting only a few hundred femtoseconds, making them indispensable for applications such as eye surgery, biological imaging, optical frequency combs, atomic clocks, and micromachining. However, their high pulse energies have traditionally required bulky tabletop systems because integrating them onto photonic chips introduced nonlinear optical effects that destabilized the laser pulses. Overcoming this limitation has long been considered one of the most difficult problems in integrated photonics.
The research team, led by scientists at the Swiss Federal Institute of Technology Lausanne (EPFL), solved the problem by revisiting a largely overlooked laser architecture known as the Mamyshev oscillator. Originally proposed in 1998, the design places a nonlinear waveguide between two optical filters, allowing high-intensity laser pulses to broaden across a wider range of wavelengths while filtering out weaker light that could disrupt stable operation. Because the architecture requires no additional chip components, it proved well suited for photonic integration.
The prototype delivers pulses of 1.05 nanojoules lasting just 147 femtoseconds, performance comparable to conventional laboratory femtosecond lasers. Although the laser cavity measures 42 centimeters in length, it can be folded into an area roughly the size of a match head on the chip. The wafer-scale manufacturing process also makes it possible to fabricate more than a thousand such laser cavities simultaneously, significantly reducing production costs.
The advancement could enable portable instruments for environmental monitoring, field medical diagnostics, spectroscopy, and precision sensing while supporting compact optical atomic clocks for future navigation and communication systems. More broadly, the work demonstrates that revisiting established concepts with modern photonic technologies can unlock solutions to longstanding engineering challenges, bringing laboratory-grade optical performance into compact, mass-producible devices.