Polymer Materials for U-Shaped Optic Fiber Sensors: A Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript reports a review of polymer materials for U-shape optical fiber sensors. The paper is well organized and clearly presented. As a review paper I guess it is qualified to publish in this journal. However, I would suggest the title to be changed as “Polymer Materials For U-Shape Optic Fiber Sensors: a Review”. The original title carries “Materials Characterization” to which the current version does not fully support, as it does not contain sufficient coverage and depth to be called “material characterization”.

Author Response

Comment: This manuscript reports a review of polymer materials for U-shape optical fiber sensors. The paper is well organized and clearly presented. As a review paper I guess it is qualified to publish in this journal. However, I would suggest the title to be changed as “Polymer Materials For U-Shape Optic Fiber Sensors: a Review”. The original title carries “Materials Characterization” to which the current version does not fully support, as it does not contain sufficient coverage and depth to be called “material characterization”.

Response: We would like to sincerely thank you for the time and effort you have dedicated to reviewing our manuscript. We fully agree that removing the word 'characterization' from the title enhances the article's clarity and better aligns with its content. The title has been changed to “Polymer Materials For U-Shape Optic Fiber Sensors: a Review” as recommended.

Reviewer 2 Report

Comments and Suggestions for Authors

The paper is a mixture of quite fundamental fiber optics knowledge with more advanced material engineering applied for fiber sensors. I would prefer less fundamental data and more advanced considerations concerning subtle details of complex fiber sensors and relevant material choices for them. The paper seems to be an extensive review of the quite numerable references. In this sense the review is good and valuable. 

Author Response

Comment: The paper is a mixture of quite fundamental fiber optics knowledge with more advanced material engineering applied for fiber sensors. I would prefer less fundamental data and more advanced considerations concerning subtle details of complex fiber sensors and relevant material choices for them. The paper seems to be an extensive review of the quite numerable references. In this sense the review is good and valuable. 

Response: Thank you for your positive and constructive review. We greatly appreciate your feedback and are pleased to hear that you found the review valuable. In response to your suggestion, we have expanded the section with fiber sensors application with more details about used material and several new applications.

Reviewer 3 Report

Comments and Suggestions for Authors

Polymer based fiber has been used as sensors for many years since it has many properties such as high flexibility, resistance to electromagnetic field/wave. Sokolowski et al give a review on polymer materials in this manuscript, including PMMA, PC, PS, HOFs, et al. This might be useful for others. Thus I recommend to publish this paper in the Photonics after the listed issues are addressed.

1.        The Abstract is not long enough. As a review paper, some key points should be given in the Abstract. I suggest adding more introduction on principles of sensing mechanisms, and detail of applications of U-shape fiber sensors in Line 18-19 of Abstract.

2.        The figure 1 (a) show the number of reported results on “POF sensor” from the Google Scholar search. Here, we can see that there is an obvious increase from 2021. I don’t know if the authors can explain it?

3.        In Section 3 Applications of U-shape POF, authors should add some details of some important applications, such as the range of temperature from Re. 35, sugar concentration in water, the detail of sensitivity from Re.24. The present form is not enough for as a review paper.

4.        In the Section 4.1, I suggest adding a table to show the typical conventional POFs, including their full names and abbreviations. Then this table can replace Line 234-238.

Author Response

Comments: Polymer based fiber has been used as sensors for many years since it has many properties such as high flexibility, resistance to electromagnetic field/wave. Sokolowski et al give a review on polymer materials in this manuscript, including PMMA, PC, PS, HOFs, et al. This might be useful for others. Thus I recommend to publish this paper in the Photonics after the listed issues are addressed.

1. The Abstract is not long enough. As a review paper, some key points should be given in the Abstract. I suggest adding more introduction on principles of sensing mechanisms, and detail of applications of U-shape fiber sensors in Line 18-19 of Abstract.
2. The figure 1 (a) show the number of reported results on “POF sensor” from the Google Scholar search. Here, we can see that there is an obvious increase from 2021. I don’t know if the authors can explain it?
3. In Section 3 Applications of U-shape POF, authors should add some details of some important applications, such as the range of temperature from Re. 35, sugar concentration in water, the detail of sensitivity from Re.24. The present form is not enough for as a review paper.
4. In the Section 4.1, I suggest adding a table to show the typical conventional POFs, including their full names and abbreviations. Then this table can replace Line 234-238.

Response 1: Thank you for your constructive review. We greatly appreciate your feedback. The abstract has been rewritten to better align your suggestion. We hope now we’re ensuring a clearer and more concise summary of our work. New version of abstract:

Fiber optic sensors have gained popularity for last decades. It is due its numerous advantages such as good metrological parameters, biocompatibility, resistance to magnetic and electric field, as well as environmental pollution. However, those built from glass fiber have one main disad-vantage – they are fragile, can be easily damage even by the presence of the vibration. Due to the enormous progress made by the material research recently it is possible to build such a sensor with polymer fibers. Although those fibers have worse transmission parameters comparing to the telecommunication fibers, they give us the possibility to realized flexible fiber optic sensor. Taking into consideration other advantages of such fibers as biocompatibility, electromagnetic resistance and even biodegradation characteristic, as well as a variety of materials we can use, it can be seem that those materials can fill the niche in the fiber optic sensors are. This paper aims to provide researchers with guidelines on the factors to consider when choosing a material for bent fiber optic sensors depending on the application.

Response 2: To answer the question about the increase in interest in POF sensors on Figure 1 we have added two likely suppositions to the article in line 55-59: The spikes in interest in POFs observed during 2016–2017 and 2020–2021 are likely attributable to the introduction of fiber optic-based technologies in the automotive industry, the growing interest in 3D printing and the potential for manufacturing POFs using similar methods, as well as the increasing focus on utilizing POFs in medical diagnostics, particularly in response to the COVID-19 pandemic.

Response 3: We agree that Section 3, which focuses on applications could be expanded. We have added the missing details, several new applications and references. Additionally, we created a table featuring several selected sensors with their metrological parameters.

Response 4: A new table ‘Standard and novel materials for polymer optic fibers’ has been added to Chapter 4 instead of list grouping the types of polymers used in optical fiber production, as recommended to enhance clarity and organization. Thank you once again for your insightful comments, which have significantly contributed to improving the manuscript.