Because they vary in terms of core size, light source, signal and laser wavelength, singlemode and multimode fiber can't be interchanged or spliced together. Doing so can result in enough data loss to prevent your network from working properly. In many applications of fiber optics, it is necessary to connect fiber ends (terminations) in some way such that light from one fiber can get into the other fiber without losing too much of its optical power. Examples are fiber lasers and systems for optical fiber communications. How it works: A media converter has two ports: one for SMF and one for MMF.
