Experimental Observation of Low Noise and Low Drift in a Laser-Driven Fiber Optic Gyroscope

Lloyd, Seth W.; Fan, Shanhui; Digonnet, Michel J. F.

doi:10.1109/jlt.2013.2261285

Cited by 27 publications

(14 citation statements)

References 10 publications

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“…This analysis also established that when the coherence length of light L c is larger than the length L of the sensing coil the drift is small, Noise and bias error due to polarization coupling in a fiber optic gyroscope Jacob Chamoun, and Michel J. F. Digonnet e.g., only ~35 μrad for a 150-m coil. In the other regime (L c < L), as the linewidth is increased the backscatteringinduced drift decreases rapidly [10], as confirmed experimentally [7]. The backscattering noise also decreases to a very low level (e.g., below 1 µrad√Hz for a linewidth of ~10 MHz or greater).…”

Section: Introductionsupporting

confidence: 65%

“…Finally, if need be the Kerr-induced drift can be further reduced by orders of magnitude by using light of sufficiently broad linewidth [6]. In a recent FOG utilizing a laser with a 10-MHz linewidth, the calculated Kerr-induced drift (30-40 nrad) was negligible compared to other sources of drift [7]. The Kerr-induced drift is therefore regarded as insignificant.…”

Section: Introductionmentioning

confidence: 99%

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Noise and Bias Error Due to Polarization Coupling in a Fiber Optic Gyroscope

Chamoun

Digonnet

2015

J. Lightwave Technol.

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This paper reports a comprehensive model of the noise and drift induced by polarization coupling in a fiber optic gyroscope (FOG) interrogated with a laser of arbitrary linewidth. It includes the effects of dynamic phase biasing, a realistic description of laser phase noise, and polarization-dependent loss. This model yields concise analytical expressions for the noise and drift dependencies on the laser linewidth, the fiber length and holding parameter h, and the fractional power launched into the unwanted polarization at the input to the sensing coil. For all realistic FOG parameter sets the polarization-coupling noise is found to be insignificant. For a 1-km coil, a typical holding parameter (h = 10 -5 ), and push-pull modulation, the drift is only ~1 µrad up to a linewidth of ~100 MHz, which is far lower than previously believed. The drift decreases to even lower values for larger linewidths. Experimental measurements of the noise and drift in a 150-m FOG and their dependence on laser linewidth support these predictions. Birefringence modulation can be brought to bear to reduce this residual drift enough to meet the requirement for aircraft inertial navigation. Ultimately, this analysis shows that low polarization coupling error can be obtained without the use of a broadband source.Index Terms-Fiber optic gyroscope, laser phase noise, optical polarization, polarization nonreciprocity error, Sagnac interferometer 0733-8724 (c)

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Section: Introductionsupporting

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Noise and Bias Error Due to Polarization Coupling in a Fiber Optic Gyroscope

Chamoun

Digonnet

2015

J. Lightwave Technol.

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“…In part as a result of these improvements, we have shown that in a FOG utilizing a 150-m length of conventional polarization-maintaining (PM) fiber the Kerr-induced drift was negligible because the two powers counterpropagating in the coil were less than 35 µW, and the slow fluctuations between them were measured over several hours to be less than 1% [5]. The Kerr-induced drift calculated from these fluctuations is in the range of 30-40 nrad, which was well below the observed drift [5].…”

Section: Laser-driven Fiber Optic Gyroscopementioning

confidence: 99%

The Fiber Optic Gyroscope: Past and Present

Digonnet

2014

Frontiers in Optics 2014

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A brief summary of the performance limitations of fiber optic gyroscopes interrogated with a broadband light source is presented, followed by a description of the status of current research efforts to push back these limitations by using an air-core fiber instead of a conventional fiber in the sensing coil, and/or coherent instead of incoherent light. Current status of the fiber optic gyroscopeFirst demonstrated shortly after the advent of single-mode fibers in the mid-1970s, the fiber-optic gyroscope (FOG) is one of the oldest and most successful fiber sensors. Commercialized since around 1985, it is widely used for applications as varied as ship navigation, stabilization, and north finding. This success is rooted in part in the fact that the FOG's sensing element is a Sagnac loop, a two-wave common-path interferometer that is inherently reciprocal and thus highly stable against most external perturbations. Equally instrumental is the use of broadband (incoherent) light to interrogate it. Incoherent light was shown very early on that it essentially eliminates the three detrimental non-reciprocal effects that take place in the fiber loop and contribute to most of the noise and/or drift in the output of the FOG, namely the intensity-dependent nonlinear Kerr effect, coherent backscattering, and polarization coupling. A fourth limitation is the Shupe effect. When the temperature of the sensing coil is subjected to a transient temperature gradient, the two signals counter-propagating in the loop experience slightly different time-dependent phase shifts, and the output drifts. It was also critical to the success of the FOG that the Shupe effect was effectively mitigated by special coil windings (e.g., quadrupolar), as well as other solutions such as modeling.Unfortunately, the adoption of a broadband source introduced two limitations. First, broadband sources such as Er-doped superfluorescent fiber sources (SFS) suffer from excess noise that typically far exceeds shot noise, which limits the FOG's minimum detectable rotation rate. Second, the FOG scale factor, which relates the measured output signal to the rotation rate, must be extremely stable (~1 ppm) for aircraft inertial navigation, the holy grail of gyroscope applications. This scale factor being inversely proportional to the mean wavelength of the light, the latter must have a comparable stability, which is difficult to achieve with broadband light. In addition, even after applying the aforementioned corrective measures the drift due to the Shupe effect is still difficult to control in practice. These hurdles are compounded by the need to keep the cost, size, and energy consumption of the FOG low enough to be competitive with the ring laser gyroscope, which is accurate and stable enough to navigate aircrafts. Air-core fiber optic gyroscopeIn the last decade two new directions have been investigated to push back these fundamental limitations. The first one is replacing the conventional (solid-core) single-mode fiber used in the sensing loop by a photonic-bandga...

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“…For the inertial north finding technology is not dependent on the outside world, it has become one of the important guarantees for the weapon system realizing autonomic, fast, mobile, and accurate targeting goals [3,4]. Fiber optic gyroscope (FOG) north-finder is one of new inertial north-finding technologies, which is increasingly used in defense and civil applications.…”

Section: Introductionmentioning

confidence: 99%

Fiber optic gyroscope dynamic north-finder algorithm modeling and analysis based on Simulink

Zhang

Liu

2017

Photonic Sens

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Abstract:In view of the problems such as the lower automation level and the insufficient precision of the traditional fiber optic gyroscope (FOG) static north-finder, this paper focuses on the in-depth analysis of the FOG dynamic north-finder principle and algorithm. The simulation model of the FOG dynamic north found algorithm with the least square method by points is established using Simulink toolbox, and then the platform rotation speed and sampling frequency, which affect FOG dynamic north found precision obviously, are simulated and calculated, and the optimization analysis is carried out as a key consideration. The simulation results show that, when the platform rotation speed is between 4.5 °/s and 8.5 °/s and the sampling frequency is at about 50 Hz in the case of using the parameters of this paper, the FOG dynamic north finding system can reach the higher precision. And the conclusions can provide the reference and validation for the engineering and practical of FOG dynamic north-finder.

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Experimental Observation of Low Noise and Low Drift in a Laser-Driven Fiber Optic Gyroscope

Cited by 27 publications

References 10 publications

Noise and Bias Error Due to Polarization Coupling in a Fiber Optic Gyroscope

Noise and Bias Error Due to Polarization Coupling in a Fiber Optic Gyroscope

The Fiber Optic Gyroscope: Past and Present

Fiber optic gyroscope dynamic north-finder algorithm modeling and analysis based on Simulink

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