Compensation of the laser parameter fluctuations in large ring-laser gyros: a Kalman filter approach

Beghi, Alessandro; Belfi, Jacopo; Beverini, N.; Bouhadef, B.; Cuccato, Davide; Virgilio, A. Di; Ortolan, A.

doi:10.1364/ao.51.007518

Cited by 29 publications

(43 citation statements)

References 22 publications

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“…On the other hand, with the characterization of laser active medium (single pass gain and plasma dispersion function), we can achieve a good accuracy of the rotation estimate. In this respect, we already developed [10] an arXiv:1309.4694v3 [physics.optics] 4 Oct 2013 algorithm for the identification of the Lamb parameters for excess gain minus losses α 1,2 , backscattering amplitude r 1,2 and phases ε 1,2 , that are associated with cavity dissipation. After providing a raw estimate of the laser medium gain, we run an extended Kalman filter that is able to remove a fraction of the backscattering induced drift from the Earth rotation rate measurements.…”

Section: Introductionmentioning

confidence: 99%

Controlling the non-linear intracavity dynamics of large He–Ne laser gyroscopes

et al. 2014

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A model based on Lamb's theory of gas lasers is applied to a He-Ne ring laser gyroscope to estimate and remove the laser dynamics contribution from the rotation measurements. The intensities of the counter-propagating laser beams exiting one cavity mirror are continuously observed together with a monitor of the laser population inversion. These observables, once properly calibrated with a dedicated procedure, allow us to estimate cold cavity and active medium parameters driving the main part of the nonlinearities of the system. The parameters identification and noise subtraction procedure has been verified by means of a Monte Carlo study of the system, and experimentally tested on the G-PISA ring laser oriented with the normal to the ring plane almost parallel to the Earth rotation axis. In this configuration the Earth rotation-rate provides the maximum Sagnac effect while the contribution of the orientation error is reduced at minimum. After the subtraction of laser dynamics by a Kalman filter, the relative systematic errors of G-PISA reduce from 50 to 5 parts in 10 3 and can be attributed to the residual uncertainties on geometrical scale factor and orientation of the ring.

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Section: Introductionmentioning

confidence: 99%

Controlling the non-linear intracavity dynamics of large He–Ne laser gyroscopes

et al. 2014

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“…In conclusion, we have developed a large-scale PRG, which has a sensitivity of 2 × 10 −9 rad/s/ √ Hz. It has a comparable sensitivity with the heterolithic active laser gyros with similar sizes [13,32], though it is still one order of magnitude worse than that of the monolithic ring laser C-II [1]. To our knowledge, this is the best result among all large scale PRGs [12,23] and we have not yet reached a fundamental limit.…”

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confidence: 88%

Large-scale passive laser gyroscope for earth rotation sensing

Liu

Zhang

et al. 2019

Opt. Lett.

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Earth rotation sensing has many applications in different disciplines, such as for the monitoring of ground motions, the establishment of UT1 and the test of the relativistic Lense-Thirring effect on the ground. We report the development of a 1 m × 1 m heterolithic passive resonant gyroscope (PRG). By locking a pair of laser beams to adjacent modes of the square ring cavity in the clockwise and counter-clockwise directions, we achieve a rotation resolution of about 2 × 10 −9 rad/s at an integration time of 1000 s. The sensitivity of the PRG for rotations reaches a level of 2 × 10 −9 rad/s/ √ Hz in the 5-100 Hz region, currently limited by the detection noise, residual amplitude modulation and the mechanical instability of the cavity. Our initial results improve the reported rotation sensitivity of the PRGs and indicate that PRGs have a great potential for highresolution Earth rotation sensing.Many large scale ring laser gyroscopes (RLG) have been built over the last three decades with extremely high sensitivity and stability [1]. These large ring lasers along with the developed fiber optic gyros have found applications in different fields like geodesy [1], seismology [1][2][3][4] and fundamental physics tests [5][6][7]. The monolithic G-ring experimentally resolves a rotation rate of 3.5 × 10 −13 rad/s over 1000 s and detects the Chandler and the annual wobble of the Earth [8,9]. The successful operation of two really large heterolithic RLGs, namely UG-1 and UG-2 with enclosed areas of 367 m 2 and 834 m 2 , demonstrate the feasibility of constructing giant rotation sensors [10,11]. Laser gyros are also used to improve the seismic isolation system for ground-based gravitationalwave antennas [12,13]. Moreover, an ambitious plan named GINGER has been proposed, focusing on measurement of the Lense-Thirring effect in a terrestrial laboratory [14]. Highly sensitive interferometric fiber optical gyroscopes (I-FOG) are developed mainly for applications in navigation and platform control, with a sensitivity in the order of 10 −8 ∼ 10 −9 rad/s/ √ Hz. Such rotational sensors with low self-noise are also suitable for applications in geosciences [15][16][17].The measurement principle of RLGs is based on the Sagnac effect: the counter propagating beams in a ring cavity will see a different round trip time if the ring cavity is rotating in the optical plane. This effect was first described by Sagnac in 1913 [18]. In 1963, Macek and Davis utilized a ring cavity that contains He-Ne gas to lase at the 1.153 µm line, which demonstrated rotation sensing [19]. This is considered to be the first active RLG. A passive gyro was successfully realized by Ezekiel and Balsamo in 1977 [20], where an external laser is split into two beams and locked to a passive ring cavity in the clockwise (CW) and counter-clockwise (CCW) direction. The rotation rate is determined by measuring the resonance frequency difference of the ring cavity in the opposite directions. A modern PRG, used as a tilt sensor, recently reported a sensitivity of 10 −8 rad/s/...

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“…On this apparatus we will test also the technique for reducing the effect of back-scattering. We have built [12] a model of the gas laser operation that is based on the Lamb formalism [13] extended by Aronowitz [14,15] to ring cavities. In this theory, the laser action has been modelled at the 3 rd order in atomic polarization, producing a coupled set of equations relating the field amplitude and phase of the two opposite laser beams in terms of a set of effective parameters.…”

Section: Laser Stability Controlmentioning

confidence: 99%