A Fabry Perot laser diode (FP laser diode) is the most common type of laser diode, having a laser resonator which is a Fabry Perot interferometer.

Fabry Perot laser is the most common communication laser . In many situations Fabry Perot laser gives good service. However, because it produces a relatively wide spectral width, Fabry Perot laser is not considered suitable for applications requiring extended distances, coherent reception, or wavelength multiplexing.

The Fabry Perot Laser ( FP laser ), also known as the Fabry Perot Interferometer (FPI),is widely used in the telecommunications industry, astronomy, and many other fields. This lasers primary application is for low-data-rate short distance transmission over distances of up to 20 kilometers.

It should be noted that the FP laser is a more advanced version or substitute for the DFB (Distributed Feedback Laser ) laser.

The spectrum width is the fundamental distinction between DFB and Fabry Perot lasers. On the one hand, the Fabry Perot laser has a wide spectrum width and is a multi-longitudinal mode laser, whereas the DFB laser has a narrow spectrum width and is a single longitudinal mode laser.