What is optical fiber?

As a kid, if you ever tied a string between two tin cans to talk to your friend… then you’ll be familiar with the idea of how optical fibers work. But unlike the string, optical fibers can carry various data over long distance in pulses of light. This means you can receive emails or any other information from any part of the world in a blink of an eye. Optical Fibers actually form the backbone of the internet and telecommunications. Today, there are over 420 submarine cables in service, stretching over 1.1 million km around the world.

So how can this light be sent so far?

It is made possible through a phenomenon called Total Internal Reflection. As you know, when shining a flashlight, the light tends to scatter over distance. But this thin, flexible, and ultra-pure glass that is Optic Fiber manages to carry the data over cities and continents. This is because the cable is made up of 3 parts- the glass Core that is surrounded by an outer layer called Cladding and a Protective Sheath. Both the glass and the cladding have an inherent property called the Refractive Index which can essentially be used to measure how fast light can travel through something. For the process to work, the core has to have a slightly higher refractive index than the cladding. This allows the light inside to be reflected in a zigzag pattern and carry along the optic fiber over a long distance.

Now in theory, this seems like it should be enough to do the trick. However, reality always has a way of interfering. You see, optic fibers just as most things have small imperfections. These imperfections are so small that you could only see them at a molecular level. Yet they still cause some of the light to scatter- weakening the signal over distance. Eventually, this causes the signal to become so weak that it can’t even be understood by the equipment on the other end. This loss of signal strength is called Attenuation and can be solved with use of amplifiers which are placed in places that the signal starts to weaken. These amplifiers pick up on the signal from the weak light and boost the light so it can travel a longer distance.

Optical Fiber Vs Copper Wiring

Right off the bat, optical fibers are far better than copper when it comes to long distance communications. In fact, it is so much better that this comparison will mostly just highlight the benefits of using optical fiber. For instance, optic fibers are not only more cost effective than copper wiring it is also more power efficient. It even goes farther than copper wiring without requiring a boost. Optical fibers are as thin as a strand of hair and doesn’t cause any electromagnetic interference to the cables around it. This allows them to be bundled in one large cable to transfer huge amounts of data without taking up too much space.

Optical Fiber in Bangladesh

In 2006, Bangladesh reached a milestone in overseas connectivity when a large-capacity undersea (submarine) optical fiber cable was laid under the Bay of Bengal to connect Cox’s Bazar with the SEA-MEA-WE-4 (Southeast Asia-Middle East-Western Europe 4) Global Fiber Optic Network. This SEA-MEA-WE-4 has a total capacity of 1280 Gbits/sec and has a combined length of 19,000 km. The submarine cable’s allocation for Bangladesh is about 14 Gigabits/sec. The successful completion of this connection has resulted in a substantial increase in overseas connection, due to the larger bandwidth. This meant that the cost of overseas calls dropped significantly and people could enjoy a faster internet connection without having to pay too much.