fiber optic cables are used to send messages at high speeds and at great distances. There exists a fiber optic cable traveling from New Jersey to England! fiber optic cables work by sending pulsing light through a specific material. since light is the fastest thing in the universe, fiber optic cables are the fastest form of communication in the known universe. as you know, light travels at different speeds when its inside of a different median. the ratio of the speed of light in air to the speed inside of the material is known as the index of refraction. a higher index of refraction means that light moves slower through the material. the core of a fiber optic cable has a much higher index of refraction than the outer layer. when light travels through the core, it is reflected off the boundary between the materials. this allows the cables to bend and not lose light.