Compact potential sensor for spacecraft based on a silicon photonic waveguide

Satellites charge up due to incoming electrons and ions, resulting in an electrical potential difference (ΔV) between the satellite and outer space. This can cause electrostatic discharge (ESD) events, damaging electronic devices. To reduce failures due to ESD, sensors monitoring the ΔV can be helpful. Due to spacecraft’s restrictions, the sensors should be as small as possible. While small potential sensors in terrestrial applications are often based on electrical conduction in semiconductors, such sensors are not suitable for space application due to a weak resistance to cosmic radiation and ESD. Here, we report a compact sensor based on another sensing method: the utilization of light absorption in a silicon photonic waveguide. We performed experiments in a vacuum chamber simulating the space plasma environment to demonstrate that the light attenuation in the waveguide depends on the ΔV. Our results further indicate that our sensor exhibits a high resistance to ESD.