Gyroscope on a Photonic Integrated Chip
The EU-funded project MERMIG (Modular CMOS photonic integrated micro-gyroscope) has made way for extra satellite payload by replacing the bulky and heavy fibre optic gyroscope. For this new generation of micro-gyroscopes, MERMIG has exploited the right mix of silicon photonic CMOS-compatible component fabrication and nano-imprint lithography laser fabrication. MERMIG has adapted both technologies for space sensor systems. The project has achieved significant advances in the modelling of guided-wave optical components, which are at the heart of the technology. A complete multiphysics approach to silicon optical nanostructure, considering non-linear optics, thermal and stress effects, was carried out to outline the fundamental design rules and achieve an efficient gyrochip, able to meet industrial needs. A silicon photonic chip of 9.3 х 3.7 mm was developed, which integrated a racetrack cavity, pin junctions and a phase decoder. In addition, a specific gyro chip packaging process was developed, with specific attention paid to the optical feedthrough and thermal dissipation, in order to assure the gyrochip’s performance over the lifetime of a space mission. The seven project partners integrated the different modules (Laser, Gyro chip, and Readout) in a fully-functional optoelectronic gyroscope system breadboard. The breadboard weighed less than 1 kilogram and has a potential consumption of less than 5 watts and footprint of a few cubic centimetres, thus meeting the requirements set by the space industry. Following the MERMIG test plan, the breadboard should be further validated through bias stability and noise measurements previous to inertial system tests, which leads beyond the MERMIG duration. Performance in space environments should also be verified, focusing on radiation tests on the gyro chip. The new micro-gyroscope will be capable of withstanding the harsh environments of telecommunications missions in geostationary orbit, as well as the mass constraints typical of rovers used in robotic exploration. The photonic gyroscope circuits can be fabricated in high volumes at low cost with exciting prospects for the European space industry.
Keywords
MERMIG, gyroscope, satellite, attitude control, nanophotonics
