What is fiber optic technology? – Insight Success

The idea that information travels in a variety of ways is something we are already used to. When you talk into a landline phone, the sound from your voice is routed through a wired cable into a wall outlet (wall socket) when another cable leads it to the local telephone exchange. Mobile phones work in a different way: they use invisible radio waves to send and receive information. They use a technology known as wireless as it does not use any cables.

Fiber optic technology is the third way we transmit information. It involves sending information encoded in a light beam into a plastic or glass tube. It was originally developed in the 1950s for endoscopes to allow doctors to look inside a human body without having to cut it up first. Engineers in the 1960s found a way to use the same technology to transmit telephone calls at the speed of light (usually 186,000 miles or 300,000 km per second in a vacuum, but slow to about two-thirds of that speed in fiber optic cable).

Optical technology

Fiber optic cable consists of extremely thin wires of plastic or glass, called optical fibers. A single cable contains anywhere from 2 to several hundred wires. Each strand is less than one-tenth the thickness of a human hair and is capable of carrying up to 25,000 telephone calls, meaning that the entire fiber optic cable can easily carry millions of calls.

The current record for a “single-mode” fiber (explained below) is 178 terabits (billion bits) per second, which is enough for 100 million Zoom sessions.

Fiber optic cables use purely light-based (optical) technology to transport information between two locations. Suppose you want to use fiber optics to send some information from your own computer to your friend’s house along the way to people all over the world via underwater connectors.

You can connect your computer to a laser, and this would convert electrical information from the computer into a series of light pulses. You would then fire the laser into the fiber optic cable. The light rays would then appear at the other end after running down the cable.

Your friend would require a light detecting component in the form of a photocell to return the light pulses to electrical information that their computer could understand. So the whole device would be like an advanced version of the kind of phone that you can make from 2 baked bean boxes and a piece of string.

How does fiber optic technology work?

To move through a fiber optic cable, light signals bounce off the walls repeatedly. Each photon (small light particle) jumps into the tube. You can assume that a beam of light moving in a clear glass tube would simply leak out of the edges. However, this is not the case.

If light hits the glass at a really low angle of less than 42 degrees, it is reflected back again, as if the glass were actually a mirror. It is a phenomenon known as total internal reflection. It is one of the things that is responsible for keeping light inside the tube.

The other thing responsible for keeping the light in the tube is the structure of the cable, which consists of 2 separate parts. The main part of the cables, which is in the middle, is known as the core, and it is the bit through which the light moves.

The cladding is another layer of glass wrapped around the outside of the core. This ensures that light signals remain inside the core. It is able to do this as it is made of a different type of glass for the core.

Types of fiber optic cables

Light signals carried down through optical fibers are so-called modes. It may sound technical, but it simply refers to different ways of traveling: a state is just the path followed by a beam of light down the fiber. One mode is to make it right down the middle of the fiber. The second mode is to jump down the fiber optic cable at a low angle. In other modes, light signals jump down the fiber at other angles that are less steep or steeper.

Single-mode is the least complex type of optical fiber. It has an incredibly thin core with a diameter of about 5 to 10 microns (millionth of a meter). All the signals in a single-mode fiber move right down the center of the cable and do not jump over the edges. Single-mode fibers, packed together into a large bundle, usually carry Internet, telephone, and cable television signals. Cables like this are capable of transmitting information over 60 miles (100 km).

Multi-mode is another type of fiber optic cable. Here, each optical fiber is about 10 times larger than 1 in a single-mode cable. Therefore, light rays travel through the nucleus by following different paths (blue, orange, cyan and yellow lines). Multi-mode cables are only capable of transmitting information over relatively short distances, which is why they are often used to connect computer networks together.

A medical tool known as a gastroscope (a type of endoscope) uses even thicker fibers. The device is inserted into the patient’s throat and used to detect diseases inside the stomach. A gastroscope is a thick fiber optic cable made up of many optical fibers.

At the end of the gastroscope there is a lamp and eyepiece. The lamp lights down part of the cable into the patient’s abdomen. When light hits the abdominal walls, it is reflected into a lens at the bottom of the cable. It then travels back up another section of cable into the doctor’s eyepiece.

Other types of endoscopes work in the same way and can be used to inspect different parts of the body. An industrial version of the tool is also available, which is known as a fibercope that can be used to examine things such as inaccessible machines in aircraft engines.