DFB laser is one type of semiconductor lasers. DFB lasers use the Bragg reflection of a diffraction grating formed along an active waveguide to unify the laser longitudinal mode. DFB provides high wavelength stability and narrow linewidth.
A DFB laser is a laser diode or optical fiber laser. DFB Laser has a low linewidth grating that extends throughout the cavity rather than simply at the opposite edges. DFB Laser are single-frequency lasers, with short linewidth and effective side modes.
The standard architectures lasers need two mirrors on both sides of the active zone to form optical cavities. DFB laser has diffraction on the active region serves as a wavelength select component and provides feedback through one mirror.
Because of high output power and stability, DFB laser is primarily utilized for high data rate long-distance transmission and clean single-mode operation.