Forrest Mims' Science Experiments

Chapter 24 Connecting Fibers to LEDs and Sensors

Optical fibers are ultra-clear strands of plastic, glass, or silica consisting of a central core surrounded by a cladding and a protective coating. Light injected into the core of a fiber remains trapped until emerging from the opposite end. This lets you transmit light point-to-point with very little loss, and even bend it around corners. The light stays in the core because the cladding has a slightly higher index of refraction than the core.

Silica optical fibers are primarily used to transmit high-bandwidth data over long distances. Inexpensive plastic fibers are widely used in sensors, illuminators, and toys. They’re also used to couple light to photodiodes in environments that require ...