Plastic optical fibre sensor system design using the field programmable gate array

Extrinsic optical fibre sensor (OFS) systems use a fibre optic cable as the medium for signal propagation between the sensor and the sensor electronics using light rather than electrical signals. A range of different optical fibre sensors have been developed and electronic hardware system designs interfacing the sensor with external electronic systems devised. In this chapter, the use of the field programmable gate array (FPGA) is considered to implement the circuit functions that are required within a portable optical fibre sensor system that uses a light emitting diode (LED) as the light source, a photodiode as the light receiver and the FPGA to implement the system control, digital signal processing (DSP) and communications operations. The capabilities of the FPGA will be investigated and a case study sensor design introduced and elaborated. The OFS system will be based on the FPGA and will provide wireless communications to an external supervisory system. The chapter will commence with an overview of OFS systems and the typical architecture of the system. Then the FPGA will be introduced and discussed as a hardware alternative to a software programmed processor that is currently widely used. A case study will then be presented with a discussion into design considerations.