All About Fiber Optics

Starting with the basics, let’s break down the meaning of fiber optics. Since most people are already familiar with what fibers are, let’s just expand our knowledge in that regard and explicitly define what a fiber is:

Fiber or fibre (from Latin: fibra[1]) is a natural or man-made substance that is significantly longer than it is wide. Fibers are often used in the manufacture of other materials. The strongest engineering materials often incorporate fibers, for example carbon fiber and ultra-high-molecular-weight polyethylene.

Synthetic fibers can often be produced very cheaply and in large amounts compared to natural fibers, but for clothing natural fibers can give some benefits, such as comfort, over their synthetic counterparts.

Fiber optics or optical fibers are synthetic fibers with two transparent, tubes that do not conduct electricity. They are concentric tubes, so one surrounds the other.

The tubes function by conducting electromagnetic energy at optical wavelengths.

Let there be Light

Around 1870, Scientist John Tyndall demonstrated that light could be guided by curved streams of water.

Then in the early 20th century, the phenomenon of total internal reflection was discovered whereby the walls of thin glass fibers acted like mirrors, to transmit light. The light bounced back and forth within the fibers and it was observed that even complete images could be carried.

Snell’s law (also known as Snell–Descartes law and the law of refraction) is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media, such as water, glass, or air.’s%20law%20(also%20known%20as,water%2C%20glass%2C%20or%20air.

Snell’s law makes it possible for optical fibers to transmit light.

However, the usefulness of light guidance would not be completely appreciated until 1950, when many scientists began to think in its potential applications. They were smart enough to understand that such applications ranged from medicine, enabling the visualization of inaccessible regions of the human body, to communication networks, in replace of metal wires.

In 1950 scientists realized the potential applications of optical fibers were numerous and included medicine, communication networks, and lighting. However the primitive optical fibers created to that date were inefficient at transmitting light for any distance and without distortion. Water and, dust and dirt would further deteriorate the light emitting properties of the early optical fibers.

In the mid 1950’s Dutch Abraham van Heel added a protective covering surrounding the fiber to improve the overall efficiency.

Fiber Optics Composition

Fiber optics are made of glass, glass plus polymers or just polymers in the case of plastic optical fibers.

The most basic type of optical fiber consists of:

  • An inner cylinder with high refractive index, called the core.
  • A middle cylinder with a lower refractive index, called the cladding.
  • An outer protective polymer layer (usually polyurethane or PVC) called the jacket.