A recent study published in Nature Communications introduces a new interferometric air-core fiber optic gyroscope (IFOG) designed for high-precision navigation. The device features a quadrupolar-wound coil made from a four-tube truncated double nested antiresonant nodeless fiber (tDNANF), offering improved thermal stability and measurement accuracy.
This approach advances fiber optic gyroscope technology for aerospace, defense, geophysical research, and autonomous vehicles.
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Evolving Fiber Optic Gyroscope Design
Fiber optic gyroscopes (FOGs) are high-sensitivity rotational sensors that rely on the Sagnac effect, where two counter-propagating light beams in a fiber coil accumulate a phase shift proportional to the rotation rate. Among FOG types, closed-loop interferometric gyroscopes are valued for their sensitivity and compact construction.
However, conventional solid-core silica fibers used in most FOGs are susceptible to environmental factors such as temperature changes, mechanical stress, magnetic interference, and radiation, which can introduce bias errors and reduce reliability in demanding conditions.
Optical Fiber Design for Enhanced Performance
The authors designed, fabricated, and characterized a four-tube tDNANF for use in high-performance IFOGs. To overcome the limitations of conventional silica-core fibers, they investigated air-core fiber designs, particularly antiresonant hollow-core fibers (ARFs), which offer low loss, high birefringence, and improved modal purity.
The tDNANF was specifically engineered to achieve nearly an order of magnitude higher birefringence than previous designs, enabling better polarization maintenance across a broad spectral range. Its cladding structure, with nested glass tubes, improves light confinement and suppresses higher-order modes. The fiber was fabricated using thermal drawing techniques, allowing precise control over geometry and optical properties.
Finite element method (FEM) simulations were used to analyze the effective index, vector field distribution, and confinement loss of polarization modes. A 469-meter coil of tDNANF was wound in a quadrupolar configuration to minimize thermal sensitivity and integrated into an IFOG system featuring direct fiber-to-chip coupling, an amplified spontaneous emission (ASE) source, a multifunction integrated optics chip (MIOC), and a photodetector.
Furthermore, performance was evaluated using the cut-back method and spatially resolved imaging to measure propagation and macrobend loss. This comprehensive approach demonstrated the tDNANF-based IFOG's potential for superior bias stability, low loss, and robust thermal performance in demanding navigation applications.
Performance Metrics and Key Findings
The outcomes showed that the tDNANF-based IFOG achieved exceptional performance, marking it as the first navigation-grade air-core fiber optic gyroscope. It exhibited an angular random walk (ARW) of 0.00383°h-1/2 and a bias instability (BI) drift of 0.0017°h-1, indicating significant improvements in stability and sensitivity over existing FOG technologies.
The tDNANF also demonstrated a substantial reduction in thermal sensitivity, being 9.24 to 10.68 times lower than conventional polarization-maintaining solid-core fibers, with thermal phase error reductions observed across different temperature ranges. The fiber maintained a polarization extinction ratio (PER) of approximately 20 dB across the 1525-1565 nm wavelength range, effectively preserving linear polarization and ensuring phase coherence.
Notably, the study indicated a 29.4-fold reduction in bias drift compared to earlier air-core gyroscopes. Experimental validation confirmed the gyroscope's navigation-grade resolution, outperforming prior efforts in air-core FOG development. Performance was further enhanced by reducing polarization noise and eliminating Kerr-induced effects. Using an ASE source with a 40 nm bandwidth ensured stable polarization and minimized ripple-induced errors.
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Applications in High-Precision Navigation Systems
The findings highlight the potential of tDNANF-based IFOGs for use in high-accuracy inertial navigation systems. Their performance characteristics—particularly improved thermal resilience and reduced environmental sensitivity—make them suitable for aerospace, defense, autonomous vehicles, and geological monitoring.
In aerospace applications, the system can support precise navigation for satellites and aircraft operating under extreme conditions. In the automotive sector, it enhances the reliability of navigation systems in autonomous vehicles. The fiber’s thermal stability and low-loss characteristics also make it useful for scientific applications such as seismic sensing and Earth rotation measurement.
Future research will focus on refining fiber geometry, reducing propagation loss, and expanding the operational bandwidth. Additional improvements—such as advanced modulation techniques and specialized coatings—may further enhance performance under extreme conditions. This work contributes both to the field of optical fiber development and the continued evolution of navigation technology across industries.
Journal Reference
Li, M., et al. Navigation-grade interferometric air-core antiresonant fibre optic gyroscope with enhanced thermal stability. Nat Commun 16, 3449 (2025). DOI: 10.1038/s41467-025-58381-6, https://www.nature.com/articles/s41467-025-58381-6
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