**3. Can optical fibers be used for communication and why?**

No one desires to have a slow Internet connection! I am sure you agree with me on this. It is very frustrating to have a slow Internet speed when one wants to download something or watch a favorite movie online.

Before the wireless Internet era, there used to be the wired, dial-up Internet. In this type of connection, a phone line was used to connect to the Internet. Several hours were spent only praying for a successful connection. A fast Internet was definitely a luxury during those days.

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**Figure 5.**

*Structured Light Fields in Optical Fibers DOI: http://dx.doi.org/10.5772/intechopen.85958*

answer to this question.

**3.1 Copper wire**

**3.2 Fiber optic cable**

transmitted in the form of light (**Figure 5**).

**3.3 Total internal reflection in fibers**

*Light travels in an optical fiber cable (credit: ProMotion/fotolia).*

Around 10 years back, Internet suppliers started utilizing fiber as a medium to transmit signals. The purpose behind this was that the transmission happened along these lines with minimal losses, giving a lot quicker Internet speeds. In 2014, an exploration aggregate at the Technical University of Denmark (DTU) succeeded to transfer 43 terabits for each second over a solitary optical fiber with only one laser transmitter! Therefore, what makes this fiber-optic technology lot more adept than copper wires? Let us, therefore, have a look at the two transmission media to get to an

Electrical pulses are sent through a copper wire in case of wired copper communication. How much of the signal will be retained by the time it reaches its destination is determined by the signal strength. The wire's electromagnetic field is constantly monitored for changes at the destination (for example, the router). The destination registers a "1" (logic high), when the field is strong, i.e., above a certain measurement, say, a, while a "0" (logic low) is registered if it dips below that particular measurement.

A fiber-optic cable is made from fine hair-like glass fiber, which carries light impulses that are transmitted by an LED or a laser source. Data in optical fiber are

Consider a long and flexible pipe, with its insides perfectly coated with silver halide, such that the inside is all a mirror. It is like a cylindrical mirror from inside. When you flash a source of light (a laser or may be a torch), what do you see at the other end? The light will reach the other end, regardless of whether the pipe is straight, curved, or twisted. Is not it? Yes, it will. This is because light will reflect off the sides of the flexible tube at all angles with almost negligible losses. But mirror tubes would be too bulky to handle. Thus, optical fibers are used to serve the purpose. Optical fibers are such flexible pipes made of glass instead of mirrors. It employs the principle of total internal reflection to transmit light from one to the other end.

Glass is amazingly pure; light can make it through even if it is several miles long. The glass for an optical fiber is drawn into an extremely thin strand, with a thickness comparable to that of a human hair. The glass strand is then coated in two layers of plastic.

Light rays traveling from a denser medium to a rarer medium speed up at the boundary. This causes the rays to bend when they pass from glass to air at an angle

At that point, broadband connections came in, which totally changed the Internet scene. The rates of 2–10 mbps became normal. Nonetheless, this still utilized great old copper wires as the transmission medium.
