One day in 1870, the British physicist John Tyndall went to the lecture hall of the Royal Society to explain the principle of total reflection of light. He did a simple experiment: drill a hole in a wooden bucket filled with water, and then use a lamp to illuminate the water from the top of the bucket.The results surprised the audience. It was observed that the radiant water flowed out of the small hole in the bucket, the water flow was curved, and the light followed, and the light was captured by the crooked water.

It has been found that light can travel along the fine wine ejected from the barrel; it has also been found that light can travel along curved glass rods. Why is this? Is the light no longer straight ahead? These phenomena caused the attention of Tyndall. After his research, it was found that because the density of medium such as water is larger than the surrounding matter (such as air), that is, light is emitted from the water to the air, when the angle of incidence is larger than a certain angle, the refracted light disappears and all the light is reflected back into the water. On the surface, the light seems to forward in the current.

Later, a glass silk with a high transparency and a spider silk--glass fiber was produced. When the light was incident on the glass fiber at a suitable angle, the light progressed along the curved glass fiber. Since this fiber can be used to transmit light, it is called optical fiber.