Rochester-UCSB team develops Pockels laser with ‘unprecedented’ chirp rate

04 Jun 2025

Lithium niobate/InP device shows promise for ultrafast metrology and lidar apps.

Researchers from the University of Rochester and University of California, Santa Barbara, have engineered a laser device smaller than a U.S. cent (less than 20 mm in diameter) that they say could “power everything from the lidar systems used in self-driving vehicles to gravitational wave detection”.

Current optical metrology usually requires bulky and expensive equipment to achieve delicate laser-wave control, creating a bottleneck for deploying streamlined, cost-effective systems, say the researchers.

The chip-scale laser, described in Light: Science & Applications, can perform fast and accurate measurements by precisely changing its wavelength across a broad spectrum at high fast rates — about ten quintillion (10¹⁸) times per second. Unlike traditional silicon photonics, the laser is made from lithium niobate and leverages the Pockels effect, which changes the refractive index of a material when an electric field is present.

Several applications

“There are several applications we are aiming for that can already benefit from our designs,” said Shixin Xue, a PhD student advised by Qiang Lin, the Dean’s Professor of electrical and computer engineering and optics, both of whom are among the paper’s authors.

“The first is lidar, which is already used in autonomous vehicles, but a more advanced form known as frequency-modulated continuous-wave lidar requires a large tuning range and fast tuning of the laser’s frequency, and that’s what our laser can do.”

The researchers demonstrated how their laser could be used to drive a lidar system on a spinning disc and identify the letters U and R made out of Lego blocks. They say that the miniature demonstration could be scaled up to detect vehicles and obstacles at highway speeds and distances. The team has also demonstrated how the chip-scale laser could be used for Pound-Drever-Hall (PDH) laser frequency locking, a common technique used to narrow down, stabilize, and reduce a laser’s noise.

“It’s an important process that can be used for optical clocks that can measure time with extreme precision, but you need a lot of equipment to do that,” said Xue, noting that a typical setup might require instruments the size of a desktop computer such as an intrinsic laser, an isolator, an acoustic optic modulator, and a phase modulator. “Our laser can integrate all of these things into a very small chip that can be tuned electrically.”

The research was supported in part by the U.S. Defense Advanced Research Projects Agency (DARPA) Lasers for Universal Microscale Optical Systems (LUMOS) and the U.S. National Science Foundation.