Design of a Photonic Strain Sensor Based on a Suspended Bragg Grating Reflector

The proliferation of space debris in Low Earth Orbit (LEO) poses significant risks to operational satellites and spacecraft. Effective management and mitigation of these risks require precise characterization of debris impact dynamics. This paper proposes a strain sensor with a Si3N4 Bragg grating suspended on a membrane. Designed at the communication wavelength of 1.55 μm, with a small footprint ( 100 μm2) this sensor can be integrated into the satellite structure, to measure real-time impact of pressures and associated structural deformations. The structure may be used in reflection and transmission modes, simplifying the readout and processing stages. Two-dimensional finite element method (FEM) simulation results revealed a reflection variation of 0.8 a.u. when applying a strain of 10,000 μϵ. The proposed method allows for collecting detailed data on debris size, velocity, and impact energy, which are critical for understanding the potential damage to satellites. This approach offers a promising solution for improving debris monitoring and impact prediction, contributing to developing more robust space debris mitigation strategies.