Originally led by John Dakin, the activity in this research group is primarily on optical fibre sensors, which are used to monitor or measure physical or chemical parameters. The fibre is either used as a sensor itself or is used as a convenient medium through which to interrogate a remote optical sensor head.
This is an exciting area of systems science and engineering, often involving electronics and signal processing systems in addition to optics, fibre optics and optoelectronics. Because of its multi-disciplinary nature, it is a research topic having considerable scope for invention, particularly in the area of novel sensing techniques. The majority of the research programmes are applied in nature, usually carried out with close industrial involvement.
The main activities are fibre Bragg grating and other sensors for monitoring of structural strain and integrity and crack growth in composite panels. Distributed-feedback, in-fibre Bragg grating lasers are being developed for use as ultra-precise sensors based on analysis of output wavelength or of beat frequency between two light-emitting modes. Temperature, strain and pressure are common target parameters with distributed sensing systems for monitoring temperature, strain and physical disturbance over large areas. Chemical sensors using direct spectroscopy, for example absorption, fluorescence and Raman spectroscopies and using chemical indicator probes on the end of optical fibres are under development. Gas sensors using correlation spectroscopy are now able to provide excellent fingerprinting of target gases to ensure good selectivity. Several developments from the group are currently being considered for industrial exploitation.