Distributed feedback (dfb laser diodes) integrate a grating into a cladding layer surrounding a dh laser diode. Compared to dh laser diodes, this etched (or deposited) diffraction grating offers narrower laser linewidths and high temperature stability.
The fabry-perot (fp) laser diode is the simplest type of semiconductor laser. In the fp laser diode, the two ends of the semiconductor are parallel to each other after being cut at the atomic level to form a resonant cavity. The semiconductor acts as a gain medium, and the laser typically exits from one of two highly reflective edges. fp lasers typically emit a single longitudinal mode and exhibit temperature-controlled tunability over a small spectral range
