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Optical Fibres: The Tubes That Bend Light

Optical Fibres: The Tubes That Bend Light

Have you wondered how Jio Internet reaches your home? Or do you ever think what the term ‘fiber’ stands for in Airtel Fiber? If not, don’t you worry. Because today you shall understand about Optical Fibers, the glass-tubes that do the impossible – they bend light!

If you remember Physics classes in school, you will recall that light always travels in a straight line, it never bends. But Optical Fiber Communication (OFC) is a technique that uses custom-made tubes, called Optical Fibres (OF), that can be used for transmitting information. OFs consist of thin strands of plastic or glass that use light as a medium to transmit signals. This is done by utilizing another important property of light – that of reflection.

The Fibre-Optic Communication –

OFC makes high-speed data transmission possible over long distances. In an OFC system, an electrical signal is converted into an optical signal by the transmitter. This optical signal is then transmitted over the optical fiber network. The optical signal is made of light pulses that are internally reflected through the fiber. These pulses are converted back into an electrical signal by the receiver. OFC has multiple advantages over traditional communication techniques such as high bandwidth, faster rate of data transfer, and lower signal attenuation. It is used in a wide range of applications, including telecommunications, cable television networks and internet services.

The history of optical fibers dates back to the 19th century when researchers began to study the properties of light rays and their transmission through various materials. However, it took a century for the first practical applications of fiber optics to emerge. Companies such as Corning Glass Works and Bell Labs developed fibers in 1960s and 1970s with the primary use in the field of telecommunications.

Principle of Working –

Total Internal Reflection (TIR) is the main principle behind the working of OFC. It is also the rule of Physics that makes the impossible, possible – i.e. bending of light. TIR occurs when a light wave traveling through a medium crosses into another medium at an angle larger than the critical angle, causing the wave to be reflected back into the original medium instead of refracting into the other medium.

What this essentially means that the shape and materials of a fiber optic tube are chosen such that a ray of light shall move forward by continuing to get reflected inside the transparent tube, instead of escaping from it. TIR is made possible due to a difference between the composition of 2 layers of fibre. The thin region at center, called the core, has refractive index higher than its surrounding region called the cladding.

The refractive index of a material is an important property as it determines how light is refracted when it passes through different materials. The greater the difference between the refractive indices of two materials, the greater the amount of bending of light that occurs at their interface. 

Hence, by controlling the refractive indices of the core and cladding, the light ray can be guided through the fibre length with minimal losses. This is possible as scattering and absorption of light is avoided. Due to this advantage, high-speed data transmission is possible over long distances. Thus, OFC has become an integral part of modern telecommunication systems.

The market is saturated with different types of optical fibres that serve a variety of purposes. Hence,  choice of optical fiber type depends on the specific application and its requirements such as cost, distance, bandwidth, and environmental conditions.

Elements of Fiber Optic Communication –

The basic elements of optical fiber communication are:

1. Transmitter: The transmitter converts electrical signals into optical signals that can be transmitted internally through the fiber. It consists of a LASER/LED, which emits light rays at a specific wavelength.

2. Optical fiber: The optical fiber carries the optical signal from the transmitter to the receiver. It is made of a thin strand of glass or plastic that is designed to guide light rays through the occurrence of total internal reflection.

3. Amplifier: Optical amplifiers are used to increase the strength of the optical signals as they travel through the fiber. 

4. Receiver: The receiver converts the optical signal back into an electrical signal for processing it through electronic hardware. It consists of a photodetector, which converts light into an electrical current, and a signal processing unit.

5. Coupler/Splitter: Couplers or splitters are used for splitting optical signal into multiple paths or combining multiple signals into a single path. They are used in applications such as fiber optic networks, where multiple devices need to communicate over the same fiber.

Applications of Optical Fiber Communication:

OFC has revolutionized our way of communicating and transferring information over long distances. Here are some important applications of Optical Fiber Communication:

1. Telecommunication Networks: Optical fiber cables are extensively used in telecommunication networks for transmitting audio, video, and data over long distances. High bandwidth and low attenuation, make them ideal for carrying huge chunks of information.

2. Internet: The internet relies on OFC for information transfer. Fiber-optic networks are used for transmitting data from one end to the other, making the access of information possible to us, anywhere in the world.

3. Cable television: Fiber-optic cables are used to provide TV signals to homes and businesses through a network of optical fiber cables. The high-speed transmission rates offered by them are less vulnerable to interference as compared to copper cables.

4. Bio-Medical applications: OFC is used in bio-medical applications such as endoscopy, where images of internal organs of the body are to be transmitted to a monitor outside the body. They are also used in performing laser surgeries for delivering laser energy to targeted areas of the human body.

5. Military and Defence: OFC is used in military and defence applications for securing confidential data and establishing secure connections. As OFC networks are difficult to intercept and interpret, they offer higher levels of security.

6. Industrial applications: Optical fibers are used in industries for sensing and monitoring various processes. They are used for measuring temperature, viscosity, and other physical parameters in harsh environments.

7. Aerospace and aviation: OFC networks are used in aerospace and aviation applications for establishing communication. They offer high-speed transmission rates that make them ideal for use in aviation environments. They are used extensively in space-related projects due to their lightweight.

Economic Impact of OFC:

21st century is often termed as the Era of Rapid Communication. Beginning with pigeons that delivered letters in the days of yore to today’s instant messaging, humanity has come a long way. Traversing this distance would not have been possible if not for the advances in communication technology, of which OFC is an integral component.

Now, let us look at some of the ways in which optical fibres have created a significant economic impact –

1. Increased productivity: Optical fiber networks have greatly increased productivity in industries, especially in those that rely on data transfer and communication. With faster data transmission, businesses can operate more efficiently leading to increase profitability and productivity.

2. Job creation: The deployment and maintenance of OFC networks have created many jobs, from engineers and technicians to marketing representatives. This has created a lasting positive impact on local economies and helped in reducing unemployment rates in highly populated countries.

3. Enhanced competitiveness: Countries with advanced OFC networks have an added advantage in the global market. OFC networks technology enables them to offer reliable communication services that attract investments and boost economic growth.

4. Increased investment: OFC networks require significant investment, which stimulates growth. Investment can come from private and public sectors and can cause businesses and individuals to benefit from reliable and fast communication networks.

5. Improved quality of life: Optical fiber communication has improved the quality of life for many people, especially those who live in remote areas. It has enabled access to healthcare and education facilities, and other services that were previously unreachable due to poor connectivity. 

Thus, with a market size of over USD 10 billion, optical fiber communication has engulfed the world economy. With the increasing graph of Internet of Things (IoT) adoption (click here to read more), OFC is slated to play even bigger role. Wireless broadband or internet services are subjected to higher instabilities as compared to OFC. Hence, the latter is preferred for critical applications such as Cloud Computing (read more here). Higher reliability of connection, faster data-transfer speeds and cost effectiveness are some of the advantages that have popularised the use of fibre optics for communication.

Thus, the ancient Indian concept of Vasudhaiva Kutumbakam – ‘The World is One Big Family’ – has been personified through internet, which is largely enabled by fiber optics. Who would have thought that mere bending of light would create a revolution in the field of telecommunication, ehh? Life can be unpredictable sometimes, but not your OFC internet, right?!

Vishvali Deo

Vishvali Deo is an E&TC (Electronics and Telecommunication) Engineer by education and Software Engineer by Profession. She believes that 'Technology is a Great Democratising and Equalising Force' and hence is on a mission to make the general public understand seemingly complex technologies in a simple manner.

She is convinced that the root of today's world problems lie in the past, hence she has also pursued post-graduation in History. She has a keen interest and a good grip over Economics, Political Science and Environmental Engineering. She has a penchant for working with Women and spreading Digital Literacy amongst them, with the aim of their empowerment. She also strives to provide Free Quality Education to children and counsels young adults. Besides, she is also skilled at Public Speaking, having won many awards in Elocution & Debate Competitions and Technical Paper Presentations.

Vikrant Deo

Vikrant Deo works as a Software Engineer with education in Electronics and Telecommunication Engineering. According to him, disruptive innovation is the key to achieving sustainable technological advancements. He often expresses  his technical skills and professional experiences on LinkedIn.

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