Recently, scientists from the Swiss Federal Institute of Technology (EPFL) and IBM announced the development of a new type of laser that is expected to have a significant impact on optical ranging technology.
The laser is based on lithium niobate material, which is commonly used in the field of light modulators and can control the frequency or intensity of light transmitted through the device. Lithium niobate is valuable because it can handle a large amount of optical power and has a high Pockels coefficient, which means that when an electric field is applied to it, it can change its optical properties.
Researchers have successfully created a new type of hybrid integrated tunable laser by combining lithium niobate with silicon nitride. The researchers achieved their breakthrough by combining lithium niobate with silicon nitride, which enabled them to produce a new type of hybrid integrated tunable laser.
The study was published in the March 15th issue of the journal Nature.
Adaptive Lidar Applications
This method produces a laser with low frequency noise (a measure of laser frequency stability), while enabling fast wavelength tuning - both of which are key characteristics of lasers used in optical detection and ranging (lidar) applications. Then, the developers conducted optical ranging experiments, using lasers to measure distances with high accuracy.
In addition to integrated lasers, this hybrid platform is also expected to achieve integrated transceivers for telecommunications and microwave optical transducers for quantum computing.
Professor Tobias J. Kippenberg, who is in charge of EPFL for the project, said, "The remarkable feature of this result is that lasers provide both low phase noise and fast picosecond tuning, which has never been achieved before in such a chip scale integrated laser."
Achieve breakthroughs in multiple aspects
Although recent progress has demonstrated tunable integrated lasers based on LiNbO3, the platform's full potential for demonstrating frequency agility and narrow linewidth integrated lasers has not yet been realized.
The above research reported a fast tuning laser based on a hybrid silicon nitride (Si3N4-LiNbO3) photonic platform, and demonstrated its application in coherent laser ranging. The platform is based on the heterogeneous integration of ultra-low loss Si3N4 photonic integrated circuits and thin film LiNbO3. Through direct bonding at the wafer level, it achieves much lower propagation loss (as low as 8.5 dB/m) than the previously demonstrated chip level integration. It also achieves narrow linewidth lasers through self injection locking laser diodes.
It is shown that the mixing mode of the resonator can be adjusted to 12 × Electro-optical laser frequency tuning is performed at a speed of 1015 Hz, with high linearity and low hysteresis, while maintaining a narrow linewidth. Using the hybrid integrated laser described above, researchers conducted a proof of concept coherent optical ranging (FMCW lidar) experiment. By applying LiNbO3 materials to Si3N4 photonic integrated circuits, researchers have created a platform that combines the respective advantages of thin film LiNbO3 and Si3N4, ultimately achieving precise photolithography control, mature manufacturing, and ultra-low loss.
Source: OFweek
