Optical fibres already have important applications in sensing and there is significant potential in many new sensing applications. Since our inception the University of Sydney has been active in fibre sensors.
Distributed sensors are readily realised using optical fibres. Applications such as perimeter sensing are already commercially available. A distributed temperature sensor initially developed by the University of Sydney is now commercially available.
Optical fibre sensors are particularly appealing in the electric power industry for measurement of current and voltage. Based on two different types of specialty fibre the University of Sydney has developed an optical fibre current sensor and is researching an optical fibre voltage sensor. Initial versions of the current sensor have undergone field trials and meet industry requirements. While commercialisation plans are being developed substantial research is ongoing to enhance the capabilities. A new approach to two beam interferometry (Network Independent Multiple Interrogation, or NIMI) has been developed by the University of Sydney researchers, and has proved decisively useful for the optical fibre current sensor (by making calibration unnecessary).
Bragg and long period gratings are attractive point sensors of temperature and strain. In collaboration with the CRC for Advanced Composite Structures the University of Sydney is applying its gratings and sensor system integration expertise to the development of optical fibre strain and temperature sensors for incorporation into composites for use in aircraft wings and other structures. There are many advantages to such sensors including sensitivity, low weight, compatibility and the ability to multiplex. Such sensors are also attractive for in vivo probing of elasticity (and geometry) where the smaller size and non-electrical nature of the optical strain sensors are advantages. The University of Sydney is currently embarking on research using large scale multiplexing of gratings which permits sensor arrays for security applications.
As well as temperature, electrical and magnetic fields and mechanical perturbations, special fibre can be made to sense many other aspects of the environment. The University of Sydney specialises in "D-Fibre" where the fibre core is almost exposed allowing strong interaction of the light with the external environment. Other applications being actively pursued include special fibres for medical dosimetry.
- Mark Wippich and Kathy Li Dessau, The Industrial Physicist, June-July 2003, pp 24-27.
- M.Matar, Application of the NIMI technique to the 3x3 Sagnac fiber optic current sensor - experimental results, Proceedings of the International Conference on Optical Fiber Sensors, Portland, Oregon 2002.