We found that the measurement sensitivity of an optical integrating gyroscope is fundamentally limited due to ponderomotive action of the light leading to the standard quantum limit of the rotation angle detection. The uncorrelated quantum fluctuations of power of clockwise and counterclockwise electromagnetic waves result in optical power-dependent uncertainty of the angular gyroscope position. We also show that, on the other hand, a quantum back action evading measurement of angular momentum of a gyroscope becomes feasible if proper measurement strategy is selected. The angle is perturbed in this case. This observation hints on fundamental inequivalency of integrating and rate gyroscopes.
We found that the measurement sensitivity of an optical integrating gyroscope is fundamentally limited due to ponderomotive action of the light leading to the standard quantum limit of the rotation angle detection. The uncorrelated quantum fluctuations of power of clockwise and counterclockwise electromagnetic waves result in optical power-dependent uncertainty of the angular gyroscope position. We also show that, on the other hand, a quantum back action evading measurement of angular momentum of a gyroscope becomes feasible if proper measurement strategy is selected. The angle is perturbed in this case. This observation hints on fundamental inequivalency of integrating and rate gyroscopes.
We find that the measurement sensitivity of an optical integrating gyroscope is fundamentally limited due to ponderomotive action of the light leading to the standard quantum limit of the rotation angle detection. The uncorrelated quantum fluctuations of power of clockwise and counterclockwise electromagnetic waves result in optical power-dependent uncertainty of the angular gyroscope position. We also show that, on the other hand, a quantum backaction evading measurement of the angular momentum of a gyroscope becomes feasible if the proper measurement strategy is selected. The angle is perturbed in this case. This observation hints at the fundamental inequivalence of integrating and rate gyroscopes.
We theoretically study both the technical and the fundamental quantum limitations of the sensitivity of a resonant optical gyroscope based on a high finesse optical cavity. We show that the quantum back action associated with the resonantly enhanced optical cross and self-phase modulation results in the nonlinear optics-mediated standard quantum limit (SQL) of the angle random walk of the gyroscope. We also found that the measurement sensitivity of a generic optical gyroscope is fundamentally limited due to the opto-mechanical properties of the device. Ponderomotive action of the light interrogating the gyroscope cavity leads to the opto-mechanical SQL of the rotation angle detection. The uncorrelated quantum fluctuations of power of clockwise and counterclockwise light waves result in optical power-dependent uncertainty of the angular gyroscope position.
The so-called standard quantum limits (SQL) of measurement errors of coordinate, momentum, amplitude of oscillations, energy, force etc. are due to back action of the meter on the system under test, whenever the meter responds to the coordinate of the system. These SQL are not fundamental and can be surmounted by various methods. In particular, in a coordinate measurement the SQL can be overcome by means of an appropriate correlation of conjugate meter variables. Conditions of quantum nonperturbing (nondemolition) and quasi-nonperturbing measurements of the energy of electromagnetic waves are discussed. Possible methods of these measurements are reviewed. Conditions for overcoming the SQL of wave energy measurement by the optical Kerr effect are analysed. The quantum limit of error of this measurement is discussed. The effects of dissipation, dispersion and generation of combination waves are considered. Results of experiments reported in the literature are discussed. The dependence of the quantum limit of detection of an external action upon a system on the initial state of the system is considered. The relation between the measurement error of an observable A and a perturbation of an observable B, when [A,B] is an operator, is examined.
Compared to the quantum noise in the measurement of the translational motion of a suspended mirror using laser light, the quantum noise in the measurement of the angular motion of a suspended mirror has not been investigated intensively despite its potential importance. In this article, an expression for the quantum noise in the angular motion measurement is explicitly derived. The expression indicates that one quadrature of the vacuum field of the first-order Hermite-Gaussian mode of light causes quantum sensing noise and the other causes quantum back-action noise, or in other words the first-order vacuum field is ponderomotively squeezed. It is also shown that the Gouy phase shift the light acquires between the mirror and the position of detection of the light corresponds to the homodyne angle. Therefore, the quantum back-action noise can be canceled and the standard quantum limit can be surpassed by choosing the appropriate position of detection analogously to the cancellation of quantum radiation pressure noise by choosing an appropriate homodyne angle.
Precise positioning and motion tracking are enabling development of key technologies in numerous fields of research and applications such as control, navigation, stabilization, and positioning systems for robotics, medical-imaging applications, virtual reality, computer games, and many more. While rotation sensing can be based on both mechanical and optical effects, optical gyroscopes provide the highest sensitivity and accuracy. Although the details may vary depending on the specific implementation, all optical rotation sensors exploit the Sagnac effect,1 i.e., the interference pattern resulting from the different phase shifts of waves propagating in a circular path along and opposite the direction of rotation. The classical Sagnac phase shift is determined solely by the angular velocity, the optical frequency, and the area enclosed by the closed-loop optical path, and completely independent of the medium’s other properties such as the index of refraction and its dispersion properties.2 This century-old result has been the subject of ongoing debate for several decades, both because of its fundamental nature and because it inherently limits the feasibility of attaining highly sensitive miniaturized rotation sensors. Specifically, it implies that the only ways to enhance the sensitivity and accuracy of optical gyroscopes are to either increase the optical frequency or enlarge the gyro’s area. In practice, both approaches are limited. Recent studies have pointed out the advantages of exploiting the Sagnac effect, generated by electronic resonances, in slow-3 and fast-light4 media (i.e., in which the group velocity is substantially smaller or larger than the speed of light) for fabrication of ultrasensitive optical gyroscopes. However, material properties based on slow/fast-light media suffer from inherent limitations and drawbacks. In particular, such systems are bulky, lossy, require very low temperatures, and are limited to specific wavelengths according to the material’s electronic andoptical properties. Instead, we have been focusing on photonic-resonance-based structures,5, 6 taking advantage of their flexibility, compact dimensions, and excellent optical Figure 1. Schematic of a coupled-resonator optical waveguide (CROW).
Abstract With the rapid development of micro‐nano fabrication technology, micro‐optical gyroscope technology has shown tremendous potential in integration, miniaturization, and sensitivity. The micro‐optical gyroscope is closely related to the performance of the gyroscopic system, which is realized by the light‐matter interaction and resonance enhancement. Currently, the detection range of micro‐optical gyroscopes extends from millimeter‐scale physical mechanical motion to molecular vibrations at the nanometer scale; however, their precision is challenging to surpass the standard quantum limit. The primary research objective of quantum precision measurement is to utilize quantum resources to conduct quantum‐enhanced measurements on physical system quantities, thereby surpassing the quantum limit and improving parameter measurement accuracy. In recent years, due to the rapid development in the field of quantum precision measurement, quantum gyroscope has made great progress in practical and engineering. In the future, by replacing traditional accelerometers and gyroscopes, it may be possible to develop highly integrated, low‐power, and low‐drift quantum inertial navigation systems. Based on the information disclosed by journals, conferences, and related research institutions, this paper briefly outlines the development status, basic principles, and corresponding challenges of the micro‐optical gyroscope. Additionally, this paper introduces the current theoretical and experimental progress of quantum‐enhanced gyroscopes.