Prinsip daripada Gentian Optik Struktur

Optical fiber is composed of two layers of glass with different refractive index. The inner layer is a light inner core, with a diameter ranging from a few micrometers to tens of micrometers, and the outer layer has a diameter of 0.1-0.2mm. The refractive index of inner core glass is generally 1 percent higher than that of outer glass. According to the principles of refraction and total reflection of light, when the angle at which the light strikes the interface between the inner core and outer layer is greater than the critical angle for generating total reflection, the light cannot penetrate the interface and is fully reflected.