Fibre Optic Cables

Fibre Optic Cables

News: Along with quantum optics, fibre optic communication stands on the cusp of a new era.

What is an Optical Fibre?
• An optical fibre is a thin and flexible strand of glass or plastic that can carry light signals from one end to the other.
• Optical fibres are widely used in fibre-optic communications, where they allow data transmission over long distances and at high speeds.
• Optical fibres work on the principle of total internal reflection, which means that light rays are trapped inside the fibre and do not escape through the walls.
• Optical fibres have many advantages over metal wires, such as lower loss, higher bandwidth, immunity to electromagnetic interference, and more security.

How do Optical Fibres work?
• Electromagnetic wave: Light is an electromagnetic wave with a spectrum of frequencies. Visible light, Xrays, radio waves, and thermal radiation (heat) all lie on this spectrum. Humans see the world around us via sunlight, but it took us a long time to control and guide light through fibre optic cables – or “light pipes” – to send coded signals.
• Reflection: When a beam of light falls on a glass surface, it passes through partially while the rest is reflected away. When it passes through, its path bends because the refractive index of glass is different from that of air. The refractive index is the property of a medium that determines how fast light can travel in it.
• Total internal reflection: When a beam travels in the reverse direction, i.e. from glass to air, it’s possible that it won’t enter the air. Instead, it will be completely reflected back within the glass. This phenomenon, known as total internal reflection, is the basis of guiding light across long distances without a significant loss of optical power.
• Encoding of signal: This is how signals encoded as electromagnetic waves can be fed into one end of an optical fibre, and they will reflect and bounce many times between the glass walls as they traverse several kilometres bearing the information in the signals.
• Optical waves allow a high data-transmission rate, up to several terabits per second in a single fibre. Unlike radio or copper-cable-based communication, fibre cables are also insensitive to external perturbations such as lightning and bad weather.