The aim of this project is to demonstrate the sensing capabilities of optical fibres using fibre Bragg grating technology. We will implement an intrusion detection system whereby a person’s presence along a staircase is detected through strain imposed by that person’s weight. Optical Fibres have several advantages over other types of sensor technologies: they are immune to electro-magnetic interference from external sources; they have the ability to take many measurement points along a single fibre; and they can be embedded within or bonded to structures. Bragg gratings are inserted into a fibre optic cable with a light source at one end and a light detector at the output end. Some light is reflected by the Bragg gratings and the amount of reflection detected is proportional to the amount of strain (and temperature) in the optical fibre. In this way we hope to build a highly sensitive and robust detection system. Photonic sensors are attracting much research and development; they have many useful industrial applications and will be a vital sensing technology in the future.

Dr William Shieh, Jonathan Rand, John-Paul Plazzer