Optical Fibres

• Optical fibres are thin, flexible glass or plastic fibres that are used to transmit light signals from one end to the other.
• The principle behind optical fibres is total internal reflexion. Light entering the fibre will be reflected off the walls of the fibre and continue along its path. This allows the light to travel long distances without much loss of signal.
• There are three parts to an optical fibre - the core, the cladding and the buffer coating. The core is where the light signal travels, the cladding is middle layer, and the buffer coating is the outer protective layer.
• Total internal reflexion within optical fibres only occurs when the light signal enters the fibre at an angle greater than the critical angle. If it’s less, the light will refract out of the fibre.
• The critical angle depends on the refractive indices of the core and the cladding. The refractive index of the cladding is always less than that of the core to allow total internal reflexion to occur.
• Optical fibres allow for a much greater bandwidth compared to traditional metal wire cables. This means more data can be transmitted in a shorter amount of time.
• There are two types of optical fibres, single-mode and multi-mode. Single-mode fibres only allow light to travel in one path down the core, while multi-mode fibres allow light to take multiple paths.
• There is less signal loss over long distances in single-mode fibres compared to multi-mode fibres, making single-mode fibres more suitable for long distance transmission.
• Some uses of optical fibres include telecommunications, internet data transmission, medical imaging, and military communication.
• A disadvantage of optical fibres is that they can be more expensive to install and maintain compared to traditional wire cables. However, they often provide better quality and speed of signal transmission.
• The signals in optical fibres experience less interference than traditional cables as they are less affected by electromagnetic waves.
• Within an optical fibre, light can travel as pulses or as a continuous wave depending upon the need and specification of the transmission.
• Light signals can lose energy due to absorption and scattering in the fibre. This leads to the use of repeaters or amplifiers to boost the signals over long distances.