DFB Laser is an edge-emitting semiconductor light source, which is more stable and generates a clean single-mode output. It offers smooth and tunable control of the wavelength, low-noise, and narrow spectral width, making it a cost-effective, ideal narrow linewidth laser for fibre optic communication and sensing applications. DFBs are widely used in the telecommunication industry. Besides, integrated DFB lasers are highly preferred in optical communication applications, such as DWDM, where a tunable laser signal is desired.