Sensitivity enhancement in optical gyroscopes by quasi-exceptional point

Optical gyroscopes, which utilize the Sagnac effect and high-precision optical cavities, hold significant potential for inertial navigation and precision measurement. In conventional weakly coupled schemes, however, the relationship between the dip positions of the transmission spectrum and the Hamiltonian eigenvalues breaks down, leading to inaccurate measurements and limiting sensitivity enhancement. To address this limitation, we propose what we believe to be a new mechanism for a highly sensitive optical gyroscope based on quasi-exceptional points (QEPs) in optical dimers. The QEPs manifest as degeneracies in the frequencies of the transmission dips. This mechanism establishes a direct and reliable relationship between spectral splitting and external perturbations. The results indicate that the system responds with high sensitivity to perturbations near the QEPs, following a square-root dependence. By aligning the sensing mechanism with experimentally observable quantities, this QEP-based scheme provides a more reliable approach for high-precision optical gyroscopes compared to the EP-based scheme. Quantum Fisher information analysis demonstrates that the QEP mechanism achieves superior measurement precision even in the presence of quantum noise. The proposed QEP-based sensing scheme provides a new approach to developing high-precision optical gyroscopes and non-Hermitian sensing technologies.