The aim of the MiniBRAGG project was to develop, test and manufacture a miniaturised acquisition unit for Fiber Bragg Grating (FBG) optical sensors to be remotely used for strain, pressure and temperature measurements in cabin and non-cabin areas. The development was based up-on FiberSensing’s proprietary tunable laser technology (BraggMETER) that enables multi-channel parallel acquisition over broadband tunability (100nm). This enables large sensor count to be addressed in a single compact instrument. The BraggMETER platform processing core was fully implemented in low-level electronics (microprocessors and FPGAs) that ensure high reliability, while reducing power consumption. The platform integrated an ultra-stable multi-line reference that ensures high accuracy over the full tuning range.

The BraggMETER platform relied on high speed analog to digital converters that restrict the maximum acquisition rate to 500S/s. Within the MiniBRAGG project the acquisition electronics were redesigned using high-speed comparators to increase the acquisition rate to 2000S/s, while maintaining the spectral resolution (±2pm) and reducing the power consumption. The driving electronics of the semiconductor optical amplifier that provides gain in the tunable laser cavity was redesigned to integrate three levels of overdriving protection to be complaint with ATEX.

• The envisaged instrument architecture integrated:
• the tunable laser module scanning 100nm at 2000S/s;
• the optoelectronic module that incorporates 8 independent photodetection blocks with digital gain control to ensure 20dB of dynamic range and;
• the processing module with digitalization based on multi-level high speed comparators, fast accurate spectral peak detection processing based on FPGAs and microprocessor for sensor calibration and interface through Ethernet.

All these features will be integrated into a compact equipment, that will be validated in-flight to achieve a TRL-6 at the end of the project.