High-Spatial-Resolution Dynamic Strain Measurement Based on Brillouin Optical Correlation-Domain Sensors
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe authors provide a comprehensive review of Brillouin optical correlation-domain sensors focusing on dynamic strain measurement with high spatial resolution. The paper is well organized, and I recommend publishing the manuscript. However, English could be improved further before it is finally published. The following is some examples that need to be revised:
1. Line 52, “The scattered light generates a Brillouin frequency shift (BFS) related to the sound velocity……” “Generates” could be changed to “has……with respect to the pump”?
2 2. Line 58, “When the Stokes light has a frequency equal to BFS……” This two frequencies can never be equal.
L 3. Line 60, “……in the propagating opposite……”
Many of these in the manuscript could be improved, and I recommend the authors check the entire manuscript thoroughly before it is published.
Comments on the Quality of English Language
English needs to be improved and some suggestions have been provided.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsIn this manuscript, a brief overview of the developments of dynamic strain sensing with high spatial resolution is summarized for Brillouin optical correlation domain technology. This manuscript is well organized, and the result presented in the manuscript is a good reference for readers in the field of distributed optical fiber sensing. I think the manuscript can be accepted for publication. But I have some concerns.
1. In page 3, the description of ” When the wavelength of incident light in single-mode fiber (SMF) is 1550 nm, Cε = 0.05 MHz/με, and CT = 1 MHz/℃ ” is inaccurate, as the two values are only typical ones for some SMFs.
2. The authors only provides a table to compare and analyze the four techniques, which is not enough. It is recommended that the author analyze the performance of these four technologies in general from a theoretical perspective, and these performance parameters include Distance, SR, frequency and range. Meanwhile, the authors should provide specific analysis and outlook on how to improve these performance parameters.
3. Please add some discussions on the main merits or disadvantages in the direct and external modulation schemes in Brillouin optical correlation domain technology.
Comments on the Quality of English LanguageThe quality of English language of manuscript is good.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for Authors
In the manuscript, the authors present a good account of a high spatial resolution Brillouin optical correlation domain systems with dynamic strain measurement. The manuscript contains multiple errata.
The introduction lacks proper literature review for DOFS and BOCDA/R systems, their use and applications.
The manuscript format needs adjustments (figures centering, text indentation, .. etc.)
Figures sizes need to be increased, labels and legends are in very small font. When zoomed in to see the labels the figures, figures labels and legend appear of very low quality and pixelated.
Figures quality need to be enhanced.
The subscripts in texts needs to be corrected, e.g., line 65 and line 67.
Figure annotations need to be revised. The current format is for a book chapter not an article, i.e., should label fig. 1, fig. 2, .. etc.
The use of active voice is not suitable for article. Need to correct to passive voice, e.g., "we proposed" to is proposed, "we investigated" to has been investigated, "we measured" is measured.
Comments on the Quality of English Language
The authors are advised to use the help of a native speaker to revise the manuscript for linguistic errors.
There are multiple occurrences where cumbersome uncommon words were used, and use of the article word "the" was often omitted.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsThe majority of the figures should be enlarged to ensure readability.
Some of the subgraphs were not mentioned in the text (e.g. 3-2(b),4-3(b,c), 4-4 (a,b,c,d)).
The following sentence is not generally valid: "When the wavelength of incident light in single-mode fibre (SMF) is 1550 nm, Cε = 0.05 MHz/με, and CT = 1 MHz/℃".
Please provide a reference for lines 101-102 "fast Brillouin DOFS based on fast-sweep, sweep-free, and slope-assistant methods has been proposed".
Please reword the sentence (p.14 , 3.) with "Distributed measurment. The correlation-domain... relevant position of the two lights .. ".
Comments on the Quality of English LanguageIn my opinion, too many abbreviations have been used in some places, which has a negative effect on the flow of reading.
Please replace the @ in table 1 with for example " ; " or " |". Furthermore, please make the font size uniform in the table.
Please use either Figure or Fig.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors have made revisions to the manuscript according to the review comments.
