Passive, free-space heterodyne laser gyroscope

Korth, W. Z.; Heptonstall, A. W.; Hall, E. D.; Arai, K.; Gustafson, E. K.; Adhikari, R. X.

doi:10.1088/0264-9381/33/3/035004

Cited by 29 publications

(28 citation statements)

References 40 publications

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“…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. This indicates that PRGs have great potential to be a high-resolution Earth rotation sensor.…”

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confidence: 91%

“…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/ √ Hz above 0.5 Hz [12]. The operation principles of an active RLG and a PRG are the same: the resonant frequency difference of the ring cavity in the opposite directions is proportional to the rotation rate of the cavity frame itself, and can be written as:where f s is the resonant frequency difference, called arXiv:1901.05446v2 [physics.ins-det]…”

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confidence: 99%

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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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confidence: 91%

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confidence: 99%

Large-scale passive laser gyroscope for earth rotation sensing

Liu

Zhang

et al. 2019

Opt. Lett.

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“…The Sagnac effect is useful in the detention of rotational signals. Instruments based on the Sagnac effect have many applications in different fields [ 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 ]. In particular, large-scale optical gyroscopes find applications in inertial navigation, geophysical study, seismic isolation, platform stabilization, etc.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, large-scale optical gyroscopes find applications in inertial navigation, geophysical study, seismic isolation, platform stabilization, etc. [ 4 , 6 , 7 , 8 , 9 ]. Optical gyroscopes utilize the non-reciprocal phenomenon inside a ring cavity introduced by the rotation of the cavity frame based on the Sagnac effect, which means two beams would experience an unequal round-trip travel time in opposite directions inside an identical light path of a rotating ring interferometer.…”

Section: Introductionmentioning

confidence: 99%

Noise Analysis of a Passive Resonant Laser Gyroscope

Liu

Zhang

et al. 2020

Sensors

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Large-scale laser gyroscopes have found important applications in Earth sciences due to their self-sufficient property of measurement of the Earth’s rotation without any external references. In order to extend the relative rotation measurement accuracy to a better level so that it can be used for the determination of the Earth orientation parameters (EOP), we investigate the limitations in a passive resonant laser gyroscope (PRG) developed at Huazhong University of Science and Technology (HUST) to pave the way for future development. We identify the noise sources from the derived noise transfer function of the PRG. In the frequency range below 10−2Hz, the contribution of free-spectral-range (FSR) variation is the dominant limitation, which comes from the drift of the ring cavity length. In the 10−2 to 103Hz frequency range, the limitation is due to the noises of the frequency discrimination system, which mainly comes from the residual amplitude modulation (RAM) in the frequency range below 2 Hz. In addition, the noise contributed by the Mach–Zehnder-type beam combiner is also noticeable in the 0.01 to 2 Hz frequency range. Finally, possible schemes for future improvement are also discussed.

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“…Any improvement in the accurate evaluation of the backscatter noise, and in general of the systematics induced by the non linear dynamics of the lasing process, is advantageous for increasing the performance of both large and small frame RLGs. Presently there is large interest in this kind of device, large scale apparatus should further improve their sensitivity and accuracy for geodetic and fundamental physics application, and small scale and transportable devices at nrad/s sensitivity are required to improve the low frequency response of gravitational wave antennas, for the development of inertial platforms, and for seismology [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Analysis of ring laser gyroscopes including laser dynamics

et al. 2019

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Inertial sensors are important at application level and also in fundamental physics. Ring laser gyroscopes, which measure angular rotation rates, are among the most sensitive ones. Large area ring laser reach sensitivities at the level of fractions of prad/s, allowing measurements of relevant geophysical signals. Improvements of a factor 10-100 would make these instruments able to measure general relativity effects; this is the goal e.g. of the GINGER project, an Earth based experiment aiming to test the Lense-Thirring effect with an accuracy of 1%. However, the laser induces non-linearities, effects larger in small scale instruments. We discuss a novel technique to analyse data, able to reduce nonlinear laser effects. We apply this technique to data from two ring laser prototypes, and compare the precision of the measurement of the angular rotation rate obtained with the new and the standard methods. We show that the back-scatter problem of the ring laser gyroscopes is negligible with a proper analysis of the data. These results not only allow to improve the performance of large scale ring laser gyroscopes but also pave the way to the development of small scale instruments with nrad/s sensitivity, which are precious for environmental studies and as inertial platforms.

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Passive, free-space heterodyne laser gyroscope

Cited by 29 publications

References 40 publications

Large-scale passive laser gyroscope for earth rotation sensing

Large-scale passive laser gyroscope for earth rotation sensing

Noise Analysis of a Passive Resonant Laser Gyroscope

Analysis of ring laser gyroscopes including laser dynamics

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