Optical Fiber Structure Principle

Optical fibers are composed of two layers of glass with different refractive indices. The inner layer is an optical inner core, with a diameter of several micrometers to several tens of micrometers, and the diameter of the outer layer is 0.1-0.2 mm. Generally, the refractive index of the inner core glass is 1% larger than that of the outer glass. According to the principle of refraction and total reflection of light, when the angle of light hitting the interface between the inner core and the outer layer is greater than the critical angle for total reflection, the light cannot penetrate the interface and is completely reflected.