Researchers from the University of Twente's MESA+ Institute for Nanotechnology and chipmaking company LioniX International (both in Enschede, Netherlands) have developed the world's most-narrowband laser diode on a chip.1
The tunable indium phosphide/silicon nitride (InP-Si3N4) hybrid integrated-photonics laser has an intrinsic laser linewidth of only 290 Hz and a spectral coverage of 81 nm at 1550 nm.
Team leader Klaus Boller of the University of Twente notes that the laser is ten times more coherent (ten times narrower bandwidth) than any other laser on a chip.
The researchers say that the new laser will bring numerous applications within reach that include controlling movable antennae on phone masts for 5G mobile internet, faster fiber-optic data transmission, and more-accurate GPS systems and sensors for monitoring the structural integrity of buildings and bridges.
Sources:
https://www.utwente.nl/en/news/!/2017/7/54645/university-of-twente-develops-record-laser-on-chip
http://www.lionix-international.com/ultra-narrow-linewidth-tunable-laser-available/
REFERENCE:
1. Youwen Fan et al., CLEO QELS 2017, paper JTh5C.9, https://www.osapublishing.org/abstract.cfm?URI=CLEO_AT-2017-JTh5C.9