Indirectly-coupled optical resonators for anti-parity-time-symmetric gyroscopes

Optical gyroscopes, which exploit the Sagnac effect, are one of the preferred choices for high-resolution sensing of angular velocity. However, their miniaturization and integration for high-resolution sensing is still a challenge in optoelectronics research. In fact, in interferometric fiber-optic gyroscopes (IFOGs) the sensitivity is proportional to the area enclosed by the fiber-optic sensing coil. Whereas, in resonant fiber-optic gyroscopes (RFOGs) and resonant micro-optical gyroscopes (RMOGs) the sensitivity is proportional to the ratio between the area enclosed by the cavity and the perimeter of the cavity. Non-Hermitian optical architectures (especially with parity-time-symmetric Hamiltonians) have been recently proposed in literature to solve this scaling problem. In this work, an anti-parity-time-symmetric gyroscope has been designed with two resonant cavities, indirectly coupled via an auxiliary bus. At the operating condition of the so-called "exceptional point", it is possible to demonstrate that the sensitivity of the gyroscope is independent of the dimensions of the device. Finally, it will be shown that the anti-parity-time-symmetric architectures represent a better choice for angular velocity sensing than the parity-time symmetric version. An enhancement of the sensitivity of several orders of magnitude with respect to standard Sagnac-based gyros with the same footprint is expected.