Time-Delay Signature Suppression and Communications of Nanolaser Based on Phase Conjugate Feedback

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this paper, the authors use a phase conjugate feedback structure to generate a wide-band chaotic signal without a time-delay signature (TDS). Furthermore, in the two-channel communication scheme, the nanolaser (NL) realizes the combination of high-quality synchronization with low delay and two-channel transmission technique. The influence of injection parameters and mismatch of internal parameters on chaos synchronization is studied. The results show that the selection of appropriate injection parameters can make the NL output the wideband chaotic signal with hidden time-delay and high-quality synchronization performance, and enhance the security of chaotic communication. In addition, the method proposed by the authors is very interesting and well argued. Therefore, I think the manuscript can be accepted after some minor revisions.

1)    It can be seen from Figure 6 that the time-delay hiding effect of delta_f1=-15 GHz is not as good as that of delta_f1= 10 GHz and 15 GHz. Why did the author not conduct further research on delta_f1= 10 GHz and 15 GHz in subsequent studies?

2)    In Figure 7, the effects of parameter mismatch synchronization are very similar when injection strength is k_inj1=k_inj2= 300 ns^-1 and 600 ns^-1 respectively. The two situations cannot form a strong contrast, and the effects of injection strength on them cannot be explained in detail. Why did the authors not study the situation when the injection strength was less than 300 ns^-1?

3)    In Figure 8, the bandwidth of the NL should increase when the bias current is increased, but why does it decrease and what causes it?

 

Comments on the Quality of English Language

Some formatting errors should be corrected, for example, the use of abbreviations such as NLs for the word nanolasers in the abstract of the manuscript, which should be used in place of nanolasers in all subsequent content. Similarly, the section relating to time-delay signature (TDS) should also be corrected.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have explained the broadband chaotic signals generated by nanolasers whose time delay signature (TDS) is completely hidden by a phase conjugate feedback structure. The manuscript is well-written, but the author has written so many equations, which are of no use to show in the main manuscript, it can be included in the supporting information. Apart from this, I have some questions. Therefore, I suggest minor revision. I listed a few things that can be improved below:

1.       The author did not explain the origin of auto-correlation function equation and did not give any explanation about this equation. Can author explain, from where he has used this equation?

2.       In Eq 14, the author has claimed that it shows the ACF. In the denominator of this equation, does this value show the probability, if it is then square should be outside the expectation bracket (<>).

3.       According to Figure 3, it has shown that, ACF value changes when the value of F changes and it does not change with β, but there is no explanation for this dependency. Can the author give some explanation?

4.       In case 2 where frequency detuning of MNL is not equal to the frequency detuning of SNL, why did author not consider the case of positive MNL and negative SNL?

IS there any specific reason? If not, then the author should also consider this case as well and add it into the manuscript.

 

5.       The author has shown that ACF of SNL1 frequency is more affected than the SNL2 at an injection strength of 300ns^-1, why is this happening? 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This work explores the capabilities of a nanolaser in generating high-quality chaotic signals with low time delay, wide bandwidth, and high synchronization signature. The methodology involves utilizing phase conjugate feedback and injecting these signals into two slave nanolasers for parallel communication. The research investigates the impact of system parameters, such as the Purcell factor F, spontaneous radiation coupling factor β, and bias current I, on the time-delay signature (TDS) hiding and bandwidth of the chaotic output from the nanolaser. Additionally, the study explores the application of these chaotic signals in two-channel communication and delves into the effects of injection parameters and internal parameter mismatch on chaotic synchronous communication.

The findings suggest that the careful selection of injection parameters can lead to stable output of chaotic signals with time-delay hiding, bandwidth enhancement, and high unpredictability, consequently enhancing the security of chaotic communication. The paper emphasizes the theoretical guidance provided by this research for the practical application of nanolaser chaotic systems. Overall, the paper presents a comprehensive investigation into the potential of nanolasers in generating high-quality chaotic signals and their application in communication systems. The exploration of system parameters and their effects on signal characteristics and communication security adds depth to the understanding of nanolaser-based chaotic systems. The findings regarding the selection of appropriate injection parameters for stable chaotic signal output and enhanced security provide practical insights for potential real-world implementations. However, a more detailed description of the experimental setup and results would further strengthen the paper's impact and applicability in the field.

In my view, this is a good theoretical investigation and helps a lot of experimental people as the guideline! However, I asked the authors to cite more relevant work in this direction. I also suggest to cite these works too:

https://www.mdpi.com/2304-6732/10/11/1196

https://pubs.rsc.org/en/content/articlelanding/2016/nr/c5nr08979d/unauth

https://opg.optica.org/oe/fulltext.cfm?uri=oe-28-18-26421&id=437477

https://pubs.aip.org/aip/apl/article-abstract/108/17/171105/30458/Overlapping-double-potential-wells-in-a-single?redirectedFrom=fulltext

https://opg.optica.org/josab/abstract.cfm?uri=josab-40-7-1726

 

 

 

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

the revised manuscript can be accepted in the present form!

Comments on the Quality of English Language

the manuscript was written well and does not require extensive editing of English, just minor editing is okay.