Fiber optics allow for the transmission of information, like the internet and cable TV. They carry information between two places using entirely light-based technology. In a cable, there can be as little as two fibers, or as many as several hundreds. Each fiber is about as thick as a human hair. But how does it work?
For the clearest example, a laser beam can be sent down the fiber. The laser is always one color of light that travels coherently. Coherence is when waves of light line up to be in phase. Two different colors of light can never be coherent because they have different wavelengths.
The light from a laser (Light Amplified by Stimulated Emission of Radiation) will also always travel in a straight line. So why can it bend around and through a fiber or stream of water?
The fibers being used are made of glass, plastic, or a combination of the two. These all have a higher index of refraction than the air, causing the light to bend from one medium to the next. If the angle that the light is being bent is less than 42˚, then the light will bounce backwards as if it hit a mirror. This is called total internal reflection.
The light waves are guided through the optical fibers due to this phenomenon of light bouncing back and forth down the cable. This allows the light information from the beginning to be able to make it all the way to the other side without losing much energy along the way.
Written by: Mimi Garai