Electromagnetic interference does not affect fiber optic cables (EMI). If copper cables aren't put properly, they might generate electromagnetic currents that interfere with other wires and cause chaos on a network. Unlike copper wires,fiber optic cables don't conduct electricity. Power-over-fiber, or PoF, is a technique that uses a fiber optic cable to carry optical power as an energy source instead of, or in addition to, carrying data. This permits a gadget to be powered from a distance while maintaining electrical isolation from the power supply.