This document discusses the application of optical fibre. It begins by introducing optical fibre technology and its valuable characteristics such as being used to sense physical and chemical properties. The main applications of optical fibre discussed are communication systems, medicine, sensors, military, and electronics. For communication systems, optical fibre is used by telecommunications companies to transmit telephone signals, internet communication, and cable television signals. In medicine, optical fibre provides a compact, flexible conduit for light or data delivery in various medical applications such as light therapy, endoscopy, and surgical microscopy. Optical fibre is also widely used in sensors for sensing acoustic, magnetic, and other fields. The military uses optical fibre for air, sea, ground, and space applications. Electronics applications of