The MORe‑G II project pursued the conversion of a passive ring‑laser gyroscope concept into a fully functional, miniaturised prototype suitable for future series production. The core technical achievement lies in demonstrating that a passive resonator can deliver performance comparable to, or exceeding, that of conventional active ring‑laser or fibre‑based gyroscopes while avoiding the lock‑in effect that plagues active devices. Because the resonator is passive, thermal and mechanical disturbances that normally affect the fibre loop in fibre‑optic gyros are largely eliminated, and the resonator can be made shorter than the sensitive arm of an interferometric gyroscope (IFOG). This reduction in size directly supports the goal of a compact, lightweight sensor for aerospace and unmanned aerial vehicle (UAV) applications.

To realise this concept, the project leveraged components from the telecommunications sector. The use of telecom‑band optics operating in the infrared spectrum provides high‑quality, low‑cost elements such as circulators, electro‑optic modulators, and beam splitters that are fibre‑integrated, thereby simplifying the optical layout. Monolithic silicon mirrors were introduced to replace a three‑component adjustment scheme with a two‑component one, reducing the resonator alignment effort and improving mechanical stability. Mirror coatings were optimised to enhance the resonator quality factor, a critical parameter for gyroscope sensitivity. The small physical footprint of the gyroscope means that the optical signals reside in the gigahertz range, imposing stringent requirements on the electronic signal processing chain. Recent advances in high‑frequency telecommunications components now enable the design of compact, high‑bandwidth electronics capable of handling these signals, a capability that was not available a few years earlier.

The project’s technical milestones included the construction of a compact electronics platform for gyroscope control, stabilization, and signal evaluation; the optimisation of resonator quality through improved mirror coatings; and a weight reduction strategy that brings the sensor’s mass below that of existing aerospace‑grade gyroscopes. While the report does not provide explicit numerical performance figures, it emphasises that the passive resonator’s reduced size and improved stability translate into a sensor that meets the stringent accuracy, stability, and integrity requirements of navigation systems in aircraft, spacecraft, and UAVs.

Collaboration was carried out by the Institute of Microtechnology (IMT) at the Technical University of Braunschweig, the Physikalisch‑Technische Bundesanstalt (PTB) in Braunschweig, and SIOS Meßtechnik GmbH. The IMT and PTB carried out the majority of the work packages, producing detailed technical reports and final conclusions. SIOS contributed its expertise in optical metrology and resonator adjustment, developing the adjustment device and integrating all components into a unified assembly. The partnership enabled a seamless transition from laboratory concept to prototype.

The project was funded by the German Aerospace Center (DLR) under the Space Management programme, with financial support from the Federal Ministry of Economics and Technology (BMWi) pursuant to a decision of the German Bundestag (grant code 50RK1952). The MORe‑G II effort followed earlier stages— a concept study (MEMS‑RLG), a concept testing phase, and the first MORe‑G project—providing a solid foundation for the prototype development. No publications were released by SIOS during the project period, largely due to pandemic‑related conference cancellations and the company’s policy of protecting proprietary technology. The final report consolidates all technical findings and confirms that the MORe‑G concept has matured to a stage where a production‑ready, miniaturised passive ring‑laser gyroscope can be realised.