TEST BENCH AND CONTROL LOGIC DEVELOPMENT FOR DYNAMIC THERMAL CHARACTERIZATION OF OPTICAL SENSORS

The recent development of more and all electric philosophy in aerospace system design necessitates the availability of innovative sensors, able to combine minimal invasiveness, electromagnetic compatibility and high performances. Fiber Bragg Grating (FBG) sensors can meet these requirements. In particular, they can be extremely useful for monitoring rapid and localized overheating in electromechanical components. To assess the FBG sensors' ability to survey these processes, a dedicated experimental setup was developed. Following a trade-off process, an optical fiber with an FBG sensor was secured between two mechanical supports, allowing the user to manually vary the pre-load applied to the fiber. The FBG sensor, in turn, was placed on a Peltier cell that applies the thermal transient. A temperature sensor, alongside the FBG, enables the evaluation of the optical sensor's performance and the creation of the control logic for the setup. The correct assembly and operation of the system, as described and validated in this work, will enable the authors to assess specific thermal characteristics of FBG sensors, such as the effect of pre-loading on the fiber, the sensor response time and the thermal conductivity of specific adopted packaging.