An FPGA based Measurement System for a Fibre Bragg Grating (FBG) Strain Sensor

This paper presents an FPGA based measurement system used to measure the output from a fibre based Bragg grating strain sensor. The system is able to monitor the output of up to 10 demultiplexed light sources generated by the Bragg grating sensor and separated using a miniaturised monochromator. The centroid (C) of the light sources are measured using a 2048 pixel linear CCD array controlled by a Xilinx FPGA. The system scans the linear array at a rate of 2 MHz and is able to obtain sub-pixel resolution which equates resolution of 1 microstrain. The control circuit is implemented using less than 58% of the logic resources on an XCS40 device