DFB Laser :
An Optical Fiber Laser: DFB Laser By Inphenix Inc.

https://www.inphenix.com/en/distributed-feedback-lasersdfbs/

A distributed feedback laser (DFB) is a type of laser diode or optical fiber laser where the active region of the device contains a periodically structured element or diffraction grating.

The spectral width of the Distributed feedback laser is narrow so it gives high output power and emits single-longitudinal mode coherent light. In a DFB laser, the grating and the reflection are generally continuous along the cavity, instead of just being at the two ends. This changes the modal behavior considerably and makes the laser more stable.

The DFB laser is used in Optic sensors, Fiber optic sensors, Metrology, LiDAR and different spectroscopy applications.