“Researchers from King Abdullah University of Science and Technology, Saudi Arabia, claim to have produced the first InGaN-based green laser with a distributed feedback (DFB) grating.”
“The addition of this grating creates a single-wavelength source that could benefit sensing, atomic clocks, and underwater wireless optical communications, according to the team spokesman Boon Ooi.”
Compound Semiconductor Magazine, Volume 25 Issue 5 JUNE 2019
https://compoundsemiconductor.net/magazine