The Design of a Photonic Crystal Fiber for Hydrogen Cyanide Gas Detection
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe author introduces the theoretical basis and simulation results of hydrogen sensing using the designed photonic crystal fiber, but does not introduce the specific experimental scheme of hydrogen detection. The author needs to give the specific detection scheme and discuss and analyze the experimental results in the paper.
Comments on the Quality of English LanguageMinor editing of English language required
Author Response
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Reviewer 2 Report
Comments and Suggestions for AuthorsIn this paper, a new PCF is designed that gives the high sensitivity and low confinement loss in the absorption wavelength of hydrogen cyanide gas. The authors use FEM for simulating the results. However, there are several questions that need be addressed.
1. In introduction, is there any research proposing PCF design to detect hydrogen cyanide gas?
2. Please include some results to show the magnetic field immunity performance of the proposed PCF design
3. Why choose 1.533um for the wavelength?
4. If possible, please include some Experimental result to support the longer life span, magnetic field immunity, and high sensitivity of the proposed new design
5. The section 3 Mathematical engineering, the section title can be more specific
Author Response
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Reviewer 3 Report
Comments and Suggestions for AuthorsIn this paper, a new PCF is designed that gives the high sensitivity and low confinement loss in the absorption wavelength of hydrogen cyanide gas. The finite element method (FEM) is used for simulating the results. According to the results, the PCF gives a high relative sensitivity of 65.13% and a low confinement loss of 1.5×10-3dB/m at a wavelength of 1.533µm. The impact of increasing the concentration of hydrogen cyanide gas on the relative sensitivity and confinement loss is investigated. I have following comments that can be addressed in the revised manuscript.
1. It is recommended that the authors give a rational explanation for the parameterization of the sensor stomatal diameter.
2. The authors are advised to illustrate its practical application in the experiments. And suggest the most suitable scheme implemented as a sensor experimental setup arrangement
3. The curves in Figure 6 are too cluttered to see and should be optimized by the authors.
4. In the Results and Discussion section, the authors should provide a comparative analysis with other published papers on the detection of hydrogen cyanide gas.
Comments on the Quality of English Languageno
Author Response
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Reviewer 4 Report
Comments and Suggestions for AuthorsThis review report is for the manuscript titled "A new design of photonic crystal fiber for the detection of hydrogen cyanide gas" by Abdolreza Pourfathi Fard, et al from the University of Tabriz, and Brunel University London.
These are the comments for the authors to address:
1) Introduction section. The manuscript proposes a new design structure for PCF. However, the background and references used in the introduction do not contain enough design design structure from past reports. The authors should rewrite the introduction section again for greater relevance to meet the objective of their work.
2) Mathematical Equations section. While the equations presented in the manuscript are not new to the field of research, the authors should give ample credit to past reports that mentioned each of the equations.
3) Line 35, "Traditional optical fibers cause a lot of noise in the sensor. These noises are produced because of the leakage of the light from the core to the cladding region". It is unclear what noise mentioned in the manuscript is, and it cannot be found in the reference paper [5].
4) Beyond this sentence, the authors should clarify their point in the revised manuscript or use a terminology common among the optical fiber sensor community throughout the manuscript.
5) Line 40, I would like to highlight citation concerns on reference [7, 8, 10, 11]. Dr Aryan Abbaszadeh's recent papers have all been cited in the manuscript. This was not explained in the manuscript text on its reason. The author of the reference papers is affiliated with the same University of Tabriz as the authors of the manuscript. Professionally, I strongly advocate for citing research reports from higher impact factor journals. This approach would not only provide readers with a more comprehensive understanding of the referenced topics but also acknowledge and credit researchers who have pioneered this work in reputable journals.
6) Line 74, are there any past reports that closely resemble this proposed new design? The authors should include it in the manuscript.
7) Why did the authors have this design?
8) Is this related to any of the previous designs in the cited references?
9) Lines 78 and 205, the dimension of the proposed design structure is very tiny. I believe this is very difficult to achieve in fabrication and new methods of fabrication are required to make the proposed design structure. The authors should have discussed in detail in the manuscript the background and potential fabrication of this design. Lines 205-209 are very generalised and not citing important fabrication references. Without this information, the proposed design has little significance.
10) Line 132, is the simulation results from a commercial software or software written by the authors. Kindly explain and discuss in detail in the manuscript.
11) Line 135, the mesh used in the proposed design structure is an important factor in the analysis. What is the mesh size or grid size used? Kindly provide it in detail in the manuscript.
12) Line 142, another zoom-in core region image should be provided to show and explain the model profile. This is a visual quick method to check and verify the fundamental mode in the manuscript. At this point in time, I cannot give further comment on the mode profile.
13) Line 155, it appears that the authors use the maximum amplitude of the mode profile for its sensing mechanism. Have the authors considered that there are other modes when compounding their effect that could potentially affect the proposed sensing mechanism?
) Line 185, the manuscript does not explain what changes were made to the mesh model to get the corresponding concentration. The authors should explain in the manuscript what they did to achieve the 1ppm (5/15/20/etc. ppm).
Comments on the Quality of English LanguageLine 28, the abbreviations were mentioned before they were defined in line 50.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
Comments and Suggestions for Authors
Author Response
There is no comment in the second round, and the respected referee considers the answers and corrections of the first round appropriate.
Reviewer 3 Report
Comments and Suggestions for AuthorsThe structural design mentioned by this author in this paper is novel, practically applicable and the article is logically clear. The expression is clear.
Comments on the Quality of English LanguageThe English language is generally articulate, but there are some grammatical issues that need to be revised.
Author Response
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Reviewer 4 Report
Comments and Suggestions for AuthorsThis second review report is for the manuscript titled "A new design of photonic crystal fiber for the detection of hydrogen cyanide gas" by Abdolreza Pourfathi Fard, et al from the University of Tabriz, and Brunel University London.
The authors have prepared a review letter to address the comments from the first review report, such as providing more in-depth information about the simulation setup (which should have already been done in the first manuscript).
After carefully reviewing the revised manuscript, I would like to highlight the following comments for the editors to note, and authors to address:
Comment #5 "Line 40, I would like to highlight citation concerns on reference [7, 8, 10, 11]. Dr Aryan Abbaszadeh's recent papers have all been cited in the manuscript. This was not explained in the manuscript text on its reason. The author of the reference papers is affiliated with the same University of Tabriz as the authors of the manuscript. Professionally, I strongly advocate for citing research reports from higher impact factor journals. This approach would not only provide readers with a more comprehensive understanding of the referenced topics but also acknowledge and credit researchers who have pioneered this work in reputable journals."
Authors' Reply #5 "His articles are in the field of sensor design in telecommunication wavelengths. According to the reviewer's opinion, only high-quality journals have been referenced. In order to comparison with previous works, most of the selected structures are reported in high quality journals of Elsevier and OSA and IEEE."
1) In the cover letter, the authors do not provide a valid reason for the cited references. I believe the majority of the research using optical fiber is in the telecommunication wavelengths.
2) New references have been revised [Ref 3, 4, 5, 11, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 27, 28]. However, in my own opinion, it is noted that the papers are still within the regional group of researchers. It does not attempt to look at the state-of-the-art in literature.
3) Based on the new references and Table 2, the proposed 'new' design of photonic crystal fiber is still not strongly justified. Ref [17 to 24] are mostly two-layer design PCFs with modifications to the geometry.
4) Table 2 lacks information on the types of gases being sensed from the reports. Could the authors please provide clarification on whether the type of gas is relevant to the comparison? Or other parameters wavelength? How are these designs compared to commercially available hollow core fiber, for example, HC-1550-02, "Characteristic Analysis and Structural Design of Hollow-CorePhotonic Crystal Fibers with Band Gap Cladding Structure." Sensors 2021, 21(1), 284; https://doi.org/10.3390/s21010284
Comment #9 "Lines 78 and 205, the dimension of the proposed design structure is very tiny. I believe this is very difficult to achieve in fabrication and new methods of fabrication are required to make the proposed design structure. The authors should have discussed in detail in the manuscript the background and potential fabrication of this design. Lines 205-209 are very generalised and not citing important fabrication references. Without this information, the proposed design has little significance."
Authors' Reply #9 "The fabrication of PCF is considered a major issue. According to micro core holes, fabrication process of the proposed PCF may not be smooth. The minimum hole size of the proposed structure is bigger than the ones reported at [20-24]. So, the sol-gel method would be the best fabrication process. The mentioned paragraph is revised."
5) Sol-gel method is one of the many methods to construct the preforms for fiber drawing towers. Could the authors provide a reference for PCF fiber with a cladding wall similar to the proposed design in the manuscript? Additionally, it should be noted that some of the cited references also refer to ref [29] without proposing alternative solutions to the fabrication issue.
Original: Line 205 to 209 "Fabrication of the PCF designed in this paper is easy and possible due to nanotechnology. To make PCFs, various methods such as stacking and drawing [19], drilling [20], sol-gel casting [21], and extrusion [22] have been proposed. The sol-gel method is more suitable for the structures proposed in this thesis due to its flexibility in making all kinds of circular holes and microstructures."
Revised: Line 302 to 306 "The fabrication of PCF is considered a major issue. According to micro core holes, fabrication process of the proposed PCF may not be smooth. Recently a popular technique has been applied to remove the complexity of fabrication which is known as Sol –gel technique [29]. This technique is applied to fabricate any kind of micro structured optical fiber as well as PCF with different types of air hole shapes and sizes."
6) These lines are still very generalised and not citing important fabrication references that can be applied to make the proposed design. The authors should explore to expand this section to create useful insight and knowledge for readers.
Line 303, "Recently a popular technique 303 has been applied to remove the complexity of fabrication which is known as Sol–gel technique [29]."
7) This reference paper [ref 29] is published a decade ago. Can the author clarify where in the reference did Sol–gel technique resolved the issue of fabricating ultra thin cladding wall structure, for example for the core of the proposed PCF?
Comment #14 "Line 185, the manuscript does not explain what changes were made to the mesh model to get the corresponding concentration. The authors should explain in the manuscript what they did to achieve the 1ppm (5/15/20/etc. ppm)."
Authors' Reply #14 "Again, we have used the triangular type as before. The triangular type is used for meshing operation. This time the size of maximum and minimum meshes are 0.01μm and 0.0006μm. The value of curvature factor is 0.3."
8) The authors have misunderstood the question. The question here is not about the mesh size, I am asking how the model knows 1ppm at 1.553 μm. Was it done in the software?
Author Response
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