Advancements in Silicon Photonic Chips Enhance Drone Navigation

Newswise — For drones to operate autonomously and safely, it is vital that they not only ascertain their position but also comprehend their movement and rotation in real time. In environments where GPS signals are unavailable, such as indoors, urban canyons, or near sensitive infrastructure, this capability relies significantly on gyroscopes that can accurately measure angular motion.

Researchers led by Yung-Jr Hung at National Sun Yat-Sen University have made strides in addressing the challenges associated with traditional gyroscopic technology. Their research leverages silicon photonics to miniaturise the optical core of a fiber-optic gyroscope, integrating essential functions onto a compact silicon photonic chip. This innovation opens new avenues for high-precision inertial sensing in lightweight autonomous systems.

A fiber-optic gyroscope operates by sending light in opposing directions through a coiled optical fibre. The Sagnac effect causes a slight optical phase difference in the two counter-propagating beams due to rotation, which can then be detected and translated into precise measurements of rotational motion. Conventional systems typically consist of multiple discrete optical components, which contribute to increased size and complexity in assembly.

The team from NSYSU has developed a single silicon photonic chip measuring approximately 4 × 1.2 millimetres, comparable to the size of a grain of rice. This chip is fabricated using semiconductor processes akin to those employed in the manufacture of computer chips, enhancing both robustness and scalability while preserving sensing performance.

To achieve stable measurements, the researchers designed and fine-tuned on-chip photonic components that realise a polarization extinction ratio exceeding 60 decibels. This development effectively reduces unwanted signal interference. Laboratory demonstrations indicated a bias instability of around 0.1 degrees per hour, a performance level often regarded as tactical-grade, along with sensitivity sufficient to detect the rotation of the Earth, a benchmark for high-precision gyroscopes.

By harnessing CMOS-compatible silicon photonics, this methodology suggests a future where fiber-optic gyroscopes can be smaller, more cost-effective, and simpler to manufacture, all while maintaining reliability. Beyond applications in drone navigation, the same chip-scale technology has the potential to extend into robotics, autonomous vehicles, space systems, and maritime applications. For further insights into this research, readers are encouraged to explore the full press release and view the accompanying research video.