Reproducible coating and testing techniques for large core luminescent clad optical fibre probes for UV detection

This paper describes a technique for the uniform and reproducible coating of unclad optical fibres with epoxies that have been doped with photoluminescent phosphors in order to create distributed optical fibre ultra violet sensors. The technique involves spinning the fibres both axially and radially simultaneously after application of the coating to create a coating of uniform thickness. The fibres are also tested for their responses to a range of ultra violet radiation conditions controlled using a test unit specifically designed for this purpose. The test unit involves an array of ultra violet LED's that can be switched on and off in specific sequences which are controlled through a graphical user interface on a PC. This method of testing enables the interrogation and comparison of outputs when specific points are irradiated along these distributed sensors.