Stimulated Brillouin Scattering Threshold in Presence of Modulation Instability for Optical Pulse in Long Optical Fiber

Round 1

Reviewer 1 Report

In a paper entitled "Stimulated Brillouin scattering threshold in presence of modulation instability for optical pulse in long optical fiber" the authors have carried out a theoretical and experimental study of the stimulated Brillouin scattering threshold for optical pulse in the presence of modulation instability in long optical fiber. An analytical expression for the calculation of the Brillouin scattering threshold in the presence of modulation instability was derived. In order to confirm the theoretical results an experiment has been carried out which are in good agreement with the theory. 

The authors have written the manuscript quite well. Nevertheless I have a question concerning similar calculations of other authors on this topic. The authors say that similar calculations have not been carried out that reveal physical mechanisms but they do not say if there are similar experiments. As it seems to me, if there is a possibility, the authors should compare their calculations with already available experiments in addition to theirs. I have my doubts that such calculations have not been done before. The authors used rather well-known expressions for the calculation (see Eq. (1)-(3)), which were well known before. Either the authors need to be more explicit about the scientific novelty they have contributed. Otherwise it turns out that the present paper looks like the authors have calculated by known methods what they did not seem to count before and verified with an experiment what has been measured before. 

If the scientific novelty of the paper is more clearly formulated and it really is, then I recommend this paper for publication.

Author Response

Please see the attachment.

 

Author Response File: Author Response.docx

Reviewer 2 Report

The research problem that is being considered here is of  importance due to number of applications. Those  range from fiber sensors/transmission to high-power fiber lasers and amplifiers. The results obtained in the paper will be useful for fiber optic community. Authors should address in more details the following issues:

1. It would be better to present the SBS threshold value plots (vs fiber lengths etc)  in terms of the pulse peak power. Perhaps, indicate that on the right scale or give a better and complete descriptions in figure captions on pulse parameters (e.g. pulse width, peak power, etc).

2. Related to that. What is the input beam  pulse width, rep rate) for the results shown in Fig 2 (i.e. SBS threshold power vs RIN). 

3. Is the conversion to the anti-Stokes frequency being considered as well?

4. Technically, if a rectangularly shaped pulses are considered in the model then the pulse spectrum is very broad and therefore MI effect is strong. Authors should specify the exact envelope (i.e. rise- fall- times) for the pulse and indicate if the pulse is transform-limited. Why a gaussian envelope (a better example) can not be used here?

5. I did not quite understand the result shown in Fig4. Why SBS threshold value is constant while (effectively) the peak power decreases?

6. English grammar and style should be revised throughout the text. As an example I would point out to a sentence on p 4 (line 118) that does not make a lot of sense "Apparently, the oc- 118 currence of MI depletes the power remains at the central frequency seriously "

Author Response

Dear reviewer:

Thank you for your patient works and professional suggestions on this manuscript. Your comments are very helpful to this manuscript. What’s important, the comment provide guidance to our further research. Thank you again.

We have revised the manuscript carefully. We have considered carefully about all the suggestions  and revised our manuscript carefully according to your comments. The revisions are marked by the “Track Changes” function in the Microsoft Word as required.

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

A theoretical and experimental study on the stimulated Brillouin scattering threshold for optical pulse is defined. Authors just showed some theorectical approaches for previous published results. However, there are some short of the detail analysis for the article. I really doubt that could be article only for the theoretical analysis.In addition, there are some broken English grammars. Please check English grammar very carefully with native English colleague professors. Literature search and analysis for previous research is limited. Therefore, authors had better revise the manuscript more carefully. Except those major concerns, there are some additional comments to improve the quality of the manuscript.

1. Featured Application section need to be removed.

2. Data Availability Statement need to be specified.

3. In abstract section, please specify the important data.

4. Please use abbreviated journal names in reference section.

5. Please provide city and country information for conference papers.

6. Please compare your measured results with previous studies. If possible, please provide the Table with some references.

7. In the introduction section, authors just showed some previous studies. However, authors need to describe the limitation of the previous research to emphasize the proposed idea. 

8. Authors showed power ratio of the transmission distance with different input powers and noise levels in Figures 1 and 2. How about the signal to nosie ratio graph ? 

9. What is L in Equation (9)?

10. In Figure 5, are there any saturation points for the gain ?

11. Please change figure to Figure.

12. Please do not use abbreviated word if authors do not use more than twice such as BOTDA.

 

Author Response

Dear reviewer:

Thank you for your patient works and professional suggestions on this manuscript. Your comments are very helpful to this manuscript. What’s important, the comment provide guidance to our further research. Thank you again.

 We have considered carefully about all the suggestions and revised our manuscript carefully according to your comments. The revisions are marked by the “Track Changes” function in the Microsoft Word as required.

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Authors have satisfactorily addressed points of concerns

Reviewer 3 Report

Authors answered the questions very carefully so the manuscript could be acceptable.