Researchers from EPFL and IBM have created a new laser that could revolutionize optical rangefinder technology. This laser is made of lithium niobate, a material often used in optical modulators to adjust the frequency or intensity of light passing through the device.

Lithium niobate is highly valued for its high optical power and ability to control its high “Pockels coefficient”. This allows the material to change its optical properties when an electric field is applied.

The researchers made their breakthrough by combining lithium niobate with silicon nitride, allowing them to create a new type of hybrid integrated tunable laser. To do this, the team fabricated silicon nitride-based integrated circuits for light (“photonic integrated circuits”) at EPFL and then connected them to lithium niobate wafers at IBM.

A chip developed in research. Image credit: Hryhoriy Likhachev (EPFL)

This approach produced a laser with low frequency noise (a measure of the laser’s frequency stability) and yet fast wavelength tuning – both excellent qualities for a laser used for light detection and range determination (LiDAR). They then performed an optical distance experiment in which they used a laser to measure distance with high precision.

In addition to integrated lasers, the hybrid platform has the potential to realize integrated receivers for telecommunications as well as microwave optical converters for use in quantum computing.

“What is remarkable about the results is that the laser simultaneously provides low phase noise and fast petahertz adjustment per second, which has never been achieved before with an integrated chip scale laser like this,” says Professor Tobias J. Kippenberg. It’s part of the EPFL project.