Silicon photonics as a platform for the sensorization of composite aerostructure production

Carbon fiber reinforced composites are widely used in aerospace due to their low weight and high mechanical strength. Resin Transfer Molding (RTM) offers a cost-effective alternative to autoclave-based manufacturing but requires strict control over process parameters. Accurate monitoring of temperature, pressure, and the resin’s refractive index—key to assessing cure state—is essential for ensuring quality. This study introduces the first application of silicon photonic sensors in composite part manufacturing, leveraging their electrical passivity and thermal stability. Embedded in a multi-ton composite tool, the sensors—with a high thermo-optic sensitivity of 78.4 pm/°C and a linearity of 0.9787—operated under demanding RTM-6 conditions (up to 165 °C and 7 bar over six hours). Across the full temperature range (30–165 °C), they exhibited exceptional stability, enabling precise cure-state monitoring.