This thesis contains an investigation of the potential of low finesse in-fibre Fabry-Perot interferometer sensors for the measurement of strain. There are a number of areas of modern engineering applications where there is a need for an alternative to conventional resistive strain gauges; particularly where a number of such sensors can be multiplexed onto a common carrier so that one system can be used for multi-point strain measurements. Hence, the emphasis is on low finesse sensors which are suitable for multiplexing. This thesis concentrates on the use of white light interferometer (WLI) techniques to measure the optical path changes produced in the sensors by the application of strain. Since thermal effects also produce phase changes in the fibre Fabry-Perot interferometer (FFPI) which are indistinguishable from strain changes the investigations have included both thermal and strain
responses of the sensors.