So, the difference between optical fiber and glass fiber: Optical fiber is a fiber made of glass or plastic that can be used as a light conduction tool. The transmission principle is \"total reflection of light\". Glass fiber is a material composed of many extremely fine glass fibers, generally more than 3 microns in diameter. It is divided into silica, alumina, calcium oxide, boron oxide, magnesium oxide, sodium oxide and so on. The diameter of glass fiber monofilaments ranges from a few microns to more than twenty microns, equivalent to 1\/20-1\/5 of a human hair, and each bundle of fiber filaments consists of hundreds or even thousands of monofilaments.