Photonic-Assisted Receivers for Instantaneous Microwave Frequency Measurement Based on Discriminators of Resonance Type

Round 1

Reviewer 1 Report

Well written review paper, however I have some suggestions, remarks ….

Not all tables and figures are, in my opinion, positioned well – there are some which have distributed captions etc. It effect flow of results presentation.

There are some abbreviations, which are not explained (line 414: OSSB+C and line 299 MMZ, which I think it is typo).

There are two techniques, which not have sufficient references PS-FBG (only two) and Fano resonance (only one) which cannot be representative for stated technique. There should be at least 3 or more, to have some feeling.

In block diagrams for principle of operation, the signals marking on connections would enable more clear presentation of operation (maybe with ω).

Figures 5, 6 and 7 have bad resolution, as they are probably taken from original reference papers, however I suggest redrawing them. Also figure 14 is the same, and units should be in parenthesis.

At figure 13, R should be defined.

Author Response

Answers to the remarks by Reviewer # 1

 

First of all, we wish to thank the anonymous Reviewer for the precious comments that allowed us to improve the quality of the paper.

1. Not all tables and figures are, in my opinion, positioned well – there are some which have distributed captions etc. It effect flow of results presentation.

Thank you for the remark. The size of some figures have been changed so that the size of the inscriptions on them is uniform throughout the text.

2. There are some abbreviations, which are not explained (line 414: OSSB+C and line 299 MMZ, which I think it is typo).

Thank you for noticing. Abbreviations have been explained in the revised version of the article.

3. There are two techniques, which not have sufficient references PS-FBG (only two) and Fano resonance (only one) which cannot be representative for stated technique. There should be at least 3 or more, to have some feeling.

Thank you for the suggestion. The table describing the methods based on the PS-FBG has been expanded with two additional examples of implementation. As for Fano resonance, this method of IFM is currently represented by only one publication, which is also noted by the authors themselves and described as a “novel approach” in [41].

4. In block diagrams for principle of operation, the signals marking on connections would enable more clear presentation of operation (maybe with ω).

We thank the Reviewer for the remark. Only basic and principal signal descriptions have been added to the block diagrams in order not to load the diagrams.

5. Figures 5, 6 and 7 have bad resolution, as they are probably taken from original reference papers, however I suggest redrawing them. Also figure 14 is the same, and units should be in parenthesis.

Thank you for this suggestion, it was also noted by other reviewers. In the revised version of the article, they have been redrawn and finalized.

6. At figure 13, R should be defined.

R₀₁ definition added to figure description.

Reviewer 2 Report

In this manuscript, the authors presented an overview on photonics-assisted instantaneous microwave frequency measurement based on FBG, PS-FBG, integrated Fano and optical ring resonator, as well as stimulated Brillouin scattering. This overview is comprehensive, which includes the principles, advantages, disadvantages as well as other issues. I think the presented review could be of interest to those working in microwave photonics, especially in microwave photonic radars. This manuscript can be accepted for publication after appropriate revisions. Regarding the technical issues, I have following comments.

1) I suggest the authors provide more information and or compare the microwave photonic IFM, microwave photonic channelizer, and photonic scanning receiver, as all these techniques can be used to measure frequency of microwave signals.

2) Photonic IFM based on optical power monitoring is an important category, I suggest the authors include the early works on this issue in the revised manuscript.

3) I encourage the authors to extend the topic from photonic IFM based on some certain devices to more general photonic IFM.

4) The quality of some figures should be improved.

Author Response

Answers to the remarks by Reviewer # 2

 

We would like to thank the anonymous Reviewer for the comprehensive review of the paper and the valuable remarks.

1. I suggest the authors provide more information and or compare the microwave photonic IFM, microwave photonic channelizer, and photonic scanning receiver, as all these techniques can be used to measure frequency of microwave signals.

Fulfilling this suggestion requires writing a series of articles about each class of IFM or writing a separate book. A detailed description and comparison is not within the scope of the article and will require of a large amount of information for presentation. We thank the reviewer for a good idea for the next article.

2. Photonic IFM based on optical power monitoring is an important category, I suggest the authors include the early works on this issue in the revised manuscript.

Thanks you for your good suggestion. A paragraph with information about early works on IFM based on optical power monitoring is added to the introduction part in the revised version of the article.

3. I encourage the authors to extend the topic from photonic IFM based on some certain devices to more general photonic IFM.

Thank you for your suggestion. Apparently, we did not clearly enough defined the statement of the problem that we set to ourselves. Recently, there have been many general reviews on IFM devoted to generalized methods, however, the reviews do not concern selective discriminators of the resonant type, and the purpose of the article appeared from this.

4. The quality of some figures should be improved.

Thank you for this remark, figures with poor quality have been redrawn and resized to ensure the equal text size of descriptions.

Reviewer 3 Report

The manuscript “Photonic-Assisted Receivers for Instantaneous Microwave Frequency Measurement Based on Discriminators of Resonance Type” reviews photonic methods for microwave frequency measurements based on discriminators of resonance type, including fiber Bragg gratings, phase-shifted fiber Bragg gratings, optical micro-ring resonators, stimulated Brillouin scattering and integrated Fano resonators. The review will help the reader comprehensively understand the application, design, and development status of photonic receivers for instantaneous microwave frequency measurement.

The following should be addressed properly before it can be recommended to be published on Photonics.

 

(1)  Some places are needed to be double checked:

1. In line 241, “it was proposed to use not the classical …”. 

2. In line 299, “… range for the MMZ and photodetector…”. 

3. In line 536, “…two components ω0+ωRF and ω0+ωRF are formed…”. In line 542, “measured components ω0+ωRF and ω0+ωRF…”. Those components may be expressed as ω0-ωRF and ω0+ωRF.

4. In line 575, “… at less than 104 narrower than …”, 

5. In line 639, The use of “…an erbium fiber amplifier…” may be the “an erbium-doped fiber amplifier”.

6. In line 671, “Of the internal influence…”. 

(2) The authors mentioned that “An analysis of the influence of temperature on the parameters of the laser and modulator is described above”. However, the detailed analysis can’t be found in the text. The authors need to give a detailed qualitative and quantitative analysis of the influence of temperature.

(3) In Ref. [26], the scheme of the IFM technique is based on the micro-disk resonator. It seems like it is a different structure of the resonator compared to the micro-ring resonator and the Fano resonance. 

(4) I suggest the authors give a summarization about the advantages and disadvantages of those mentioned IFM techniques based on resonance type, maybe in a form of table or figure. 

Author Response

Answers to the remarks by Reviewer # 3

 

We would like to thank the anonymous Reviewer for the comprehensive review of the paper and the valuable remarks.

1. Some places are needed to be double checked:

1.1. In line 241, “it was proposed to use not the classical …”.

1.2. In line 299, “… range for the MMZ and photodetector…”.

1.3. In line 536, “…two components ω0+ωRF and ω0+ωRF are formed…”. In line 542, “measured components ω0+ωRF and ω0+ωRF…”. Those components may be expressed as ω0-ωRF and ω0+ωRF.

1.4. In line 575, “… at less than 104 narrower than …”.

1.5. In line 639, The use of “…an erbium fiber amplifier…” may be the “an erbium-doped fiber amplifier”.

1.6. In line 671, “Of the internal influence…”.

Thank you for your suggestions for text corrections. The places mentioned above has been rewritten.

2. The authors mentioned that “An analysis of the influence of temperature on the parameters of the laser and modulator is described above”. However, the detailed analysis can’t be found in the text. The authors need to give a detailed qualitative and quantitative analysis of the influence of temperature.

This phrase refers to section 2.2, describing the influence of the operating parameters of the laser and modulator on the measurement accuracy. Since this was implicitly expressed in the previous version of the text, a link to the section is indicated in the revised version of the article to specify this phrase.

3. In Ref. [26], the scheme of the IFM technique is based on the micro-disk resonator. It seems like it is a different structure of the resonator compared to the micro-ring resonator and the Fano resonance.

This error has been corrected in the revised version of the article and another publication was used for the review.

4. I suggest the authors give a summarization about the advantages and disadvantages of those mentioned IFM techniques based on resonance type, maybe in a form of table or figure.

Thank you for this suggestion. A separate paragraph with a short discussion, as well as a summary table of the implementation options with the best achieved characteristics in terms of the operational frequency range and measurement error, is given in the Conclusion section in the revised version of the article.

Round 2

Reviewer 2 Report

Some suggestions and comments of the reviewer have not been well addressed in the revised manuscript. I think the paper is not suitable for publication.