How Do Optical Fibers Conduct Light?

Light travels at different speeds through different materials, and when it transmits  from one material to another, it undergoes refraction and reflection at the interface. The angle of refraction depends on the angle of the incident light. As the angle of the incident light approaches or surpasses a specific threshold, a phenomenon known as total reflection occurs, where the refracted light disappears, and all the incident light is reflected back.

Optical fiber communication relies precisely on this principle of total reflection. When light enters the center of an optical fiber, it encounters a core with a higher refractive index (n1) compared to the surrounding cladding (n2). Additionally, the core experiences less loss than the cladding. This configuration ensures that the light undergoes total reflection, with its optical energy primarily transmitted within the core. Through continuous total reflection, light can propagate from one end of the fiber to the other. Since the core diameter is exceedingly small, and light travels along its length, the loss of optical signals is significantly lower than the transmission loss of electrical signals in traditional cables.