DFB stands for “Distributed FeedBack laser” and refers to a type of laser used in fiber optics, telecoms, spectroscopy, atomic analysis, and precise measurement tools.

They are a type of semiconductor, quantum cascade, or optical laser that spreads light in a specific way to form a single-frequency signal.

They are valued for having low noise, a tunable wavelength, and for producing an extremely stable signal that works on a single longitudinal mode. Distributed feedback lasers are also considered extremely cost-effective despite costing more than traditional lasers.