Research on Magnetic-Induced Error of Small-Sized Fiber Optic Gyro Fiber Coil in Space Environment

Round 1

Reviewer 1 Report

Optic gyro will lead to non-negligible errors, but the gyro used for low earth orbit satellite is usually unable to be equipped with a magnetic shield due to the limitation of weight. Therefore, it is necessary to establish a more accurate magnetic field error model for high-precision miniaturized gyroscopes. In this paper, authors establish a more accurate magneto-error model of fiber optic gyroscope, and carry out detailed theoretical derivation and experimental verification. I think it is worth publishing in Photonics. And this paper is consistent with the special issue "Integrated Optical Waveguide Gyro" of this journal, authors can consider being included in this special issue. But before it could be accepted, there are some issues to be dealt with.

1. The parameters of PMF in Table 1: “Clad thermal expansion coefficient” and “Coefficient of thermal expansion in stress region” are not used in the paper.

2. There are many equations in this paper, it is suggested that authors confirm the completeness of writing. For example, in Equation 8, whether i=n about E-? P11 and p12 in Equation (31) need to be explained. The torsional period of the fiber amplitude is about 0.2, does it mean that tw(z) of Equation (33) is 0.2?

3. In this paper, the specific parameters of Helmholtz coil are given. Generally, the current will also affect the temperature of Helmholtz coil. Does the error need to be considered?

4. Why is there a significant difference in the noise under the radial magnetic field and the axial magnetic field in Fig.9 and Fig.12?

5. Some figures need to be modified, including coordinates and labels, such as the horizontal axis font in Fig.4 is too small, and (a) and (b) are not added.

6. In addition, some spelling mistakes need the author's attention: "include" in line 19 should be "includes"; The "μ" in line 321 should be italicized; "axial magnetic fields" should be "axial magnetic field" .

Author Response

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Reviewer 2 Report

In this work Wong et al. have studied the magnetic induced errors of small sized Interference Fiber Optic Gyroscope. The effect of radial and axial magnetic field is determined by using Jones matrix. The authors also designed and experiment using current source, transconductance amplifier and Helmholtz coil. With this experiment authors were able to conclude that their model reduces the root mean square error of radial and axial magnetic field significantly compared to the traditional models. Overall, the work is very well written and observations are clearly described. 

 

The general idea of the paper is appealing and interesting but I could not find much to criticize due to my limited domain background. Please incorporate comments below before accepting:

 

Figure4: Figure does not specify (a) and (b). Please add.

Figure13: Please check legend spelling error.

Page11, line333: Can you please elaborate the term SLD laser for general reader?

Author Response

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Reviewer 3 Report

In the submitted manuscript, the authors investigated magnetic-induced errors in small-sized IFOG for space applications. The authors proposed a three-dimensional model for a small fiber coil in a magnetic field. Using this model, the authors analyzed the influence of the radial and axial magnetic fields on the drift of a small IFOG. To verify the developed model, the authors performed experiments to determine the IFOG drift errors associated with a magnetic field of different intensity. The experimental results are in good agreement with the calculated results obtained using the developed model. The article may be useful to specialists working in the field of development and production of small-sized IFOGs.

There are a few small remarks.

1. In the comments to Figure 2 (lines 102-109), the angles are indicated in the XOY plane, but this coordinate system is not indicated in Figure 2.

The formula for magnetic induction (line 107) uses the parameter z, but there is no explanation of what it is. Only after reading the next section does it become clear that z is the length of the fiber, and then the meaning of the ratio z/r becomes clear. These values should be explained in the text and indicated in Figure 2.

2. Section 2.2 (line 209) states that the dielectric constant of the fiber is the square of n. If n is the index of refraction, then this should be indicated, since earlier the authors introduced the parameter n as the number of micro-units (line 143).

3. Formula (17) should be checked. From simple geometrical considerations, it seems that the tangent of the angle alpha is h/2NR.

These shortcomings are not fundamental and do not affect the results obtained, but their correction will improve the quality of the paper.

Author Response

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