Corning’s iconic innovation continues to harness light and shape the way we communicate today
When we make a quick phone call, check a website, or download a video in today’s highly connected world, it’s all made possible by beams of light constantly bouncing through hair-thin strands of optical fiber.
The innovation emerged as one of Corning’s greatest success stories when scientists, in 1970, developed a way to transmit light through fiber without losing much of it along the way.
While many features of the fiber have improved enormously in the 45 years since then, the basic principles of data transmission remain the same.
So, how does fiber actually work? Let’s take a look.
When a device like your computer has information to send, that data starts out as electrical energy. A laser in the computer converts the signals to photons – tiny particles of electromagnetic energy, otherwise known as light – and sends them in rapid succession down the core of the hair-thin fiber.
Photons travel in waves through the inner core of the fiber. Because this core region has higher refractive index (i.e. light travels more slowly) than does the fiber’s outer cladding, the light signal is focused within the core and prevented from radiating out of the fiber. In addition, fiber cores are made from very high purity materials (typically Silica and Germania) to assure that the light energy is not absorbed or scattered by impurities. Radiation, absorption, and scattering are all forms of energy loss, also known as attenuation. By keeping such losses as low as possible, fiber allows light and the information it carries to travel great distances from the original source.
But if the core were the only component of the fiber, the light energy would eventually leak out, weakening the signal in a process known as attenuation. So optical fiber also includes an outer layer, or cladding, made from a different glass composition. The cladding material has a low refractive index designed to reflect light back into the core without allowing it to escape.
When the photons reach their destination, a photocell-equipped optical receiver decodes the digital light signals and converts them back into electricity, displaying the data on the other user’s computer, television, or other device.