Fiber Optics Technology used the idea that information can move in different ways, so we don’t think much about it. Wires carry the sounds of our voices from our landline telephones into a hole in the wall, where another cable takes them to a telephone exchange in our area and sends them there. Cellphones work differently. They send and receive information through radio waves that can’t be seen. This technology is called wireless because it doesn’t need wires. Fiber Optics Technology can be used thirdly, as well. A beam of light sends a coded message down a glass or plastic tube. To help doctors see inside the body without cutting it open first, it was first used for endoscopes in the 1950s. Telephone calls can now be sent at speeds of 186,000 miles or 300,000 km per second, which is the speed of light in a vacuum. In a fiber-optic cable, this speed slows to about two-thirds of this speed.
Optical technology is a way to make things that look good.
This is how a Fiber Optics Technology cable works: It has very thin strands of glass or plastic called optical fibers. One cable can have just 2 optical fibers, but it can also have many more than that. Each strand is less than a tenth of the thickness of a human hair and can carry about 25,000 telephone calls. An entire fiber-optic cable can easily carry a lot of calls, though. According to fiber expert Jeff Hecht, the current record for what’s called “a single-mode” fiber is 178 trillion bits a second. This is enough for 100 million Zoom sessions, he says.
Fiber-optic cables use only optical (light-based) technology to send information between two places. What if you wanted to move some data between computers and send it to a friend’s house down the street? You could use fiber optics to do this fiber optics could be utilized in this situation. There are lasers that you can connect your computer to. These lasers can turn electrical information from the computer into a series of light pulses that can be seen. In this case, you’d shoot a laser down a fiber-optic wire. After going down the cable, the beams of light would come out at the other end of the cable. Your acquaintance would be able to convert the light pulses back to electrical information that his or her computer could read by using a photoelectric cell (a light-detecting component). A telephone made from two baked-bean cans and a piece of string would be a lot like this.
How does fiber optics work?
Light bounces off the walls over and over again as it travels down a fiber-optic cable. It looks like a bobsleigh going down an ice run. Each photon (light particle) bounces down the pipe. Because light travels through clear glass, you might think that it would just leak out the sides. This is not the case. There is one exception to this rule: If the light hits the glass at a very low angle (less than 42 degrees), it bounces back in. It looks like the glass is a mirror at that angle. This is known as total internal reflection. Keeps light from coming out of the pipe.
This is another thing that keeps light from going out. The cable is made of two parts. There is a big piece of the cable that goes through the middle of it, which is called the core. That’s where the light goes. The cladding, which is constructed of glass, is wrapped around the outside of the core. The cladding’s job is to keep the light signals from getting out of the core. That’s why it can do this: It’s made from a different kind of glass than what’s inside. The cladding is less refractory than glass.
Fiber Optics Cable Types
There are different ways that optical fibers carry light signals down them. These ways are called modes. A mode is a path a light beam takes down the fiber. Getting down the middle of the fiber is one way. Some people bounce down the fibers at a low angle, which is another way to do it. There are also other ways to bounce down the fiber, which can be more or less steep.
When it comes to optical fiber, single-mode is the simplest type of fiber and is called that. It has a very small core that is only a few millionths of a meter across. There is only one way for signals to move in a single-mode fiber. They don’t bounce off the edges (yellow line in the diagram). Fibers that carry signals for cable TV, the Internet, and telephone calls are usually made of a single mode. They are then bundled together into a huge bundle. Information can be sent over 100 km by cables like this one that can send it (60 miles).
Another type of fiber-optic cable is called multi-mode, and it has a lot of different types of fibers. Each optical fiber in a multi-mode cable is about 10 times bigger than one in a single-mode cable, so they’re both a lot bigger. This means that light beams can travel through the core in a variety of ways (yellow, orange, blue, and cyan lines). In other words, they can travel in several different ways. Multi-mode cables can only send information over short distances. They are used to connect computer networks, for example, and are also used for other things.
When doctors poke down someone’s throat with an endoscope (also called a gastroscope, which is a type of endoscope), they use even thicker fibers to see inside their stomach. A gastroscope is a long fiber-optic cable with a lot of optical fibers in it. At the top end of a gastroscope, there is an eyepiece and a lamp that you can use to look at things. There is a lamp that shines its light down one part of a cable into the person’s stomach. When the light gets to the stomach, it bounces off the walls and into a lens at the bottom of the cable. Then, it goes up another part of the cable and into the doctor’s eyepiece again. They all work the same way and can be used to look at different parts of the body. There is also an industrial version of the tool, called a fiberscope, that can be used to look at things like hard-to-reach parts of airplane engines and other things that are hard to reach.
Uses of Fiber Optics Technology
If you shoot light down a pipe, it looks like a cool scientific party trick. You might not think there are many practical applications for something like that. But beams of light can also carry many types of information, so they can help us in many ways. This means that we don’t think about just how common fiber-optic cables have become, because the laser-powered signals they carry move far beneath our feet, deep under office floors and city streets. The technologies that use it, such as computer networking, broadcasting, medical scanning, and military equipment, do so almost unnoticeable, but they do so very well.
People now use fiber-optic cables instead of copper cables to send information over long distances because they have three big advantages over old-style copper cables.
Attenuation is less: (signal loss) Information can travel about 10 times farther before it needs to be boosted, which makes fiber networks easier and cheaper to run and maintain.
No disruption: There is no “crosstalk” (electromagnetic interference) between optical fibers, so they send information more reliably and with better signal quality than copper wires.
Higher speed: As we’ve seen, fiber-optic cables can carry a lot more data than copper cables of the same length.
You’re reading these words now because the Internet has made it possible for you to do so. You probably found this page through a search engine like Google, which has a network of huge data centers around the world that are connected by huge fiber-optic cables (and is now trying to roll out fast fiber connections to the rest of us). To get this web page, you’ve clicked on a search engine link and downloaded it from my webserver. Most of the way to you, my words have whizzed through more fiber-optic lines. As it turns out, if you have fast fiber-optic broadband, optical fiber cables do most of the work every time you go on the web. It’s only the last part of the journey (the “last mile”) from the fiber-connected cabinet on your street to your home or apartment that is done with old-fashioned wires. A lot of “likes” and “tweets” these days are carried by fiber-optic cables, not copper wires. They run under our streets and through more rural areas, and even deep beneath the oceans that connect different parts of the world. Some people say that fiber-optic cables make up almost all of the Internet and carry almost all of the world’s communication traffic. If you think of the Internet and the World Wide Web as a global spider web, the strands that hold it together are fiber-optic cables.
In general, the faster people can get on the Internet, the more things they can and will do there. The phenomenon of cloud computing was made possible by broadband Internet, which made it possible (where people store and process their data remotely, using online services instead of a home or business PC on their premises). A lot like DSL broadband, which uses ordinary telephone lines to send and receive data, the steady rollout of high-speed fiber broadband will make it much more common for people to do things like stream movies online instead of watching TV or renting DVDs. In the future, we’ll be able to track and control many more parts of our lives online through the “Internet of things.” With more fiber capacity and faster connections, we’ll be able to do this.
But fiber-optic lines don’t just send public Internet data down them. Computers used to be connected over long distances by telephone lines or copper Ethernet cables, but fiber cables are now the most common way to connect computers because they’re very cheap, secure, reliable, and have a lot more capacity. Because the public Internet isn’t very good at connecting businesses, a company could instead set up its fiber network, or it could buy space on a private fiber network. Many private computer networks use what’s called dark fiber, which sounds a little scary, but it’s just the extra space on another network that isn’t being used (optical fibers waiting to be lit up).
The Internet was cleverly designed to be able to move any kind of information for any kind of use, not just computer data. Once, the Internet used to be transported by telephone lines. Now, the fiber-optic Internet does the job. It used to be that long-distance phone calls had to go through a complicated network of copper lines and microwave links between cities. Now, most calls go through fiber-optic lines. From the 1980s onward, a lot of fiber was put down. Estimates vary, but the world’s total is thought to be a few hundred million kilometers (enough to cross the United States about a million times). In the mid-2000s, it was thought that as much as 98 percent of this was “dark fiber.” Even though more fiber is used today, it’s still thought that most networks have a third to a half of this “dark fiber.”
It was easy to send electromagnetic waves through the air from a single transmitter at the broadcasting station to a lot of antennas in people’s homes in the early 20th century. This simple idea led to radio and TV broadcasting. Radio still sends out waves through the air, but we’re just as likely to get our TV through fiber-optic cables these days, too.
Cable TV companies led the way in the 1950s and 1960s when they used coaxial cables (copper cables with a layer of metal screening wrapped around them to stop crosstalk interference). These cables carried just a few analog TV signals. From time to time, more and more people were getting their cable TV, which meant cable operators had to switch from using coaxial cable and analog broadcasting to using optical fibers and digital broadcasting. Scientists had already worked out how that might be possible. Charles Kao and George Hockham did the math in 1966, and they proved that a single optical fiber cable could carry enough data for several hundred TV channels (or several hundred thousand telephone calls). A few years later, Kao won the Nobel Prize in Physics for his “groundbreaking” work in the field of physics.
Other than being much more powerful, optical fibers don’t get as much interference, which means better picture and sound quality. They also need less amplification to boost signals so they can travel long distances, and they’re cheaper all around. As technology progresses, fiber broadband may be the way most of us watch TV. Systems like IPTV (Internet Protocol Television) may be used to serve TV shows and movies on demand, using the Internet’s standard way of transporting data, “packet switching.” The copper telephone line is still the main way for people to get information into their homes. In the future, our main way to get information from the world will be through a high-speed fiber-optic cable that can carry any kind of information.
Over 50 years ago, fiber optics was used for the first time in a good way in medical gadgets that let doctors see inside our bodies without having to cut them open. Today, gastroscopes (what these things are called) are as important as ever, but fiber optics is still bringing us important new ways to scan and diagnose.
One of the newest things is called a lab on fiber, and it involves inserting fiber-optic cables with sensors into a patient’s body. This is called a lab on a fiber. Compared to the light guides used in gastroscopes, these fibers are a lot smaller and lighter. They’re also the same size as the ones used in communication cables. They do what they do. Their body parts are lit up from the inside by something like a lamp or a laser. The doctor wants to look at a part of their body. As the light whistles through the fiber, the patient’s body changes its properties in a certain way. For example, the light’s intensity or wavelength might be changed very slightly. Interferometry is a way to figure out how the light changes. An instrument attached to the other end of the fiber can use this information to figure out important things about the patient’s body, like their temperature, blood pressure, cell pH, or the presence of medications in their circulation. This type of fiber-optic cable doesn’t just use light to see inside the patient’s body. Instead, it uses light to sense or measure the patient’s body.
Webs of fiber-optic cables connect the world’s high-tech military forces. It’s easier to picture Internet users linked together by these webs of cables. If you want to connect military bases or other places like missile launch sites or radar tracking stations, fiber-optic cables are the best way to do it. They’re cheap, lightweight, high-capacity, resistant to attack, and very safe. Because they don’t use electricity, they don’t emit electromagnetic radiation that an enemy can see. They’re also resistant to electromagnetic interference (including systematic enemy “jamming” attacks). Another advantage of fiber cables is that they aren’t as heavy as traditional copper wires, which are heavy and expensive. Fiber-optic cables are being used by tanks, military planes, and helicopters in a very slow way now. One way to save money and weight are to cut back on things like food and gas (fiber-optic cables weigh nearly 90 percent less than comparable “twisted-pair” copper cables). But optical fibers are also more reliable because they don’t have to be shielded (insulated) against lightning strikes.
Who was the inventor of fiber optics?
- the 1840s: Swiss scientist Daniel Colladon (1802–1893) discovered the light pipe. The water reflected the light internally.
- 1870: At the Royal Society in London, John Tyndall (1820–1893) demonstrated internal reflection. He lit a pitcher of water. When he poured water from the jug, the light followed the water’s path. Fiber optics use this concept of “bending light.” True fiber-optics pioneer Colladon, Tyndall is frequently credited.
- the 1930s: Two German students tried to create a gastroscope using light pipes.
- the 1950s: In London, British physicist Harold Hopkins (1918–1994) and Indian physicist Narinder Kapany (1926–2021) sent a picture down a light pipe made of thousands of glass fibers. Kapany was the “father of fiber
- optics” after publishing numerous scholarly articles.
- Three American scientists, Lawrence Curtiss, Basil Hirschowitz, and Wilbur Peters, created the world’s first gastroscope using fiber-optic technology.
- 1960the s: US physicists Charles Kao (1933–2018) and George Hockham (1933–2018) determined impure glass was useless for long-range fiber optics Kao proposed that a fiber-optic cable built of exceptionally pure glass might transport telephone signals over considerably greater distances, earning him the 2009 Nobel Prize in Physics.
- the 1960s: Corning Glass Company researchers created the first fiber-optic telephone cable.
- 1970: Donald Keck and colleagues at Corning developed the first low-loss optical fibers.
- It was between Long Beach and Artesia, California, in 1977.
- 1988: TAT8, the first transatlantic fiber-optic telephone cable, was laid.
- According to TeleGeography, there are currently 436 fiber-optic submarine cables spanning 1.3 million kilometers (0.8 million miles). That’s up from 378 cables in 2019, yet the total distance is nearly the same.