Answer:
Light sources of fiber optics are used to inject light into a fiber optic cable. There are two varieties of light sources: laser diodes and light emitting diodes (LEDs) . They’re further differentiated by the wavelength and the type of cable.
LEDs are economical, slow in speed, easy to handle, multi mode-only, and have a wide output pattern.
Laser diodes are of expensive and faster than LED's, allow single-mode or multi mode both , and have a narrow output pattern.