An optical fibre based ultra violet and visible absorption spectroscopy system for ozone concentration monitoring

The use of optical fibres for the measurement of ozone based on the optical absorption of UV light at 254 nm and visible light at 600 nm is investigated and tested. Sensing in the UV region allows for highly sensitive detectors due to its high absorption in that region. The visible region has a significantly lower absorption of ozone and so it is possible to monitor high ozone concentrations. Calculations based on the Beer–Lambert law are presented to demonstrate the high resolution of the UV based sensor in determining the concentration of ozone in the range of 0–1 mg/l and the ability of the visible based sensor to measure high concentrations over a wide range of 25–126 mg/l.