Analysis of Kerr effect in resonator fiber optic gyros with triangular wave phase modulation

Abstract

We present an in-depth analysis of the Kerr effect in resonator fiber optic gyros (R-FOGs) based on triangular wave phase modulation. Formulations that relate gyro output to the rotation rate, the Kerr nonlinearity, and other fiber and gyro parameters are derived and used to study the effect of Kerr nonlinearity on the gyro performance. Numerical investigation shows that the Kerr effect results in a nonzero gyro output even when the gyro is at stationary, which is interpreted as an error in the measurement of rotation rate. This error was found to increase as the frequencies of the two triangular phase modulations deviate from each other, and is not zero even if the intensities of the two counterpropagating beams are exactly the same. For fixed frequencies of the triangular phase modulations, there exists an optimal intensity splitting ratio for the two counterpropagating beams, which leads to zero gyro error. Calculation shows that the measurement error due to the Kerr effect for an R-FOG with a hollow-core photonic bandgap fiber as the fiber loop can be one to two orders of magnitude smaller than an R-FOG with a conventional single mode fiber loop.

Directions of development of optical gyroscopes based on passive ring resonators

“…It is also possible to reduce the influence of the Kerr effect by rectangular modulation of the laser power with a duty ratio of 0.5 [72] or to measure the error caused by the Kerr effect and eliminate it algorithmically when processing the output signal [73]. There are passive methods of control: application of a ring resonator made of hollow photonic crystal fiber [40,45,74,75], usage of two different resonators for CW and CCW waves [45], increasing the effective cross-sectional area of the mode [76], etc. [77,78].…”

Performance analysis of an optical passive ring-resonator gyro with a hollow-core photonic bandgap fiber sensing coil

“…Using Eq. (11) and the following parameters [3,18,19]: for conventional SMF (Corning's SMF-28), η=259.81, mode field diameter = 7.5μm; for HC-PBF (Crystal fiber's HC-1550-02 fiber), η=380.53, mode field diameter = 8.4 μm, and χ=0.002. We numerically calculated the rotation rate error induced by optical Kerr effect in the OPRG with a HC-PBF coil, and compare it with the conventional SMF OPRG.…”

A New Method to Achieve Single-Polarization Guidance in Hollow-Core Negative- Curvature Fibers

“…Optical ring resonator is one of the core elements in RFOGs that determine the accuracy of RFOGs. Various optical noise sources in optical ring resonators, such as Kerr effect and Rayleigh backscatter, restrict practical applications of RFOGs [5]. Using hollow-core fibers (HCFs) instead of conventional solid-core fibers in optical ring resonators can effectively reduce the above-mentioned optical noises and thermally induced nonreciprocity owing to guiding light in air cores [2], [6].…”