Recent Advances in Optical Injection Locking for Visible Light Communication Applications

Round 1

Reviewer 1 Report

The paper by Chao Shen et al is devoted to reviewing the recent advances of optical injection locking (OIL) for visible light communication applications, i.e., invisible light color regime. The authors have analysed the enhancement effects of OIL on the characteristics of different devices. The authors have concluded that a development of OIL in visible light communication VLC) systems could function as a helpful road map for developing greater and more effective VLC networks and systems.

The paper by Chao Shen et al has the scientific merits, is of great theoretical and practical importance, and is definitely recommended for publication in the journal "Photonics" (MDPI).

The only minor points are as follows:

i) The readers would be extremely interested to learn more about future trends of OIL in VLC, so more detailed comment (a few lines) is needed in the point 5. 

ii) In order to take the possible wishes and questions of readers into account, it makes sense to expand the list of references and add a few references on the known monographies (textbooks) on optical communication systems (including OIL etc), for example, as follows:

1., Optical telecommunication systems. Ed. V.N. Gordienko. Hotline-Telecom, Moscow,2011.

2. A. V. Glushkov, Optical communication systems: Signal processing and cybersecurity, Astroprint, Odessa, 2011; A. V. Glushkov, Theory of a chaos, Astroprint, Odessa, 2012.

3. Le Nguyen Binh, Noises in Optical Communications and Photonic Systems 

PublCRC Taylor & Francis Press, 2019

ISBN 9780367870294 

4., M. Sibley, Optical Communications. Components and Systems. Springer Cham, 2020;https://doi.org/10.1007/978-3-030-34359-0 

and others at the discretion of the authors. Thanks for minor revisions. 

Author Response

Please see the attachment.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

In this review, the authors elucidated recent advances in the OIL technique, particularly in visible light color regime. The ability of the OIL approach to enhance the performance of optoelectronic devices is well-recognized and there is a vast array of existing research that has used the technology for optical communication applications. The authors presented research concerning the enhancement effects of OIL on the characteristics of different devices, which has demonstrated satisfactory increases in output power as well as high SMSR values. They also examined studies on the application of OIL in various VLC systems. This paper is generally well written and the contributions to this field are solid. This review is of potential interest to the research community of VLC and archival value. I have some minor suggestions for the authors to consider to revise this paper:

- The pictures in the paper and the words in the pictures are relatively blurred, and some words are even unclear in Figure 5. In addition, Figure 4 should be processed more carefully, and the redundant vertical lines on the right side should be removed.

- The first occurrence of "DFB" in line 79 of the paper should give the full name "distributed feedback", and then directly use its abbreviation, such as "InGaN/GaN distributed feedback laser diodes with gratings" in Table 1. Similar situations include LDs, BER, etc.

- In line 155 of the paper, "The team achieved a clear main peak in the spectrum, in contrast to the free-running one, as illustrated in the inset of Fig. 4." According to the description, "Fig. 4" should be corrected to "Fig. 3".

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

The authors have summarized the recent advancements of optical injection locking (OIL) in optical communications. The author's work provides a comprehensive picture of OIL in optical communications, a topic currently lacking sufficient review articles. Hence, I believe the scientific community would be benefitted from this article. I would like to provide some feedback for improvement:

  1. The quality of the figures in the manuscript requires improvement. It would be beneficial to enhance the resolution of the images or use higher-quality graphics for a better representation of the results. 2. On line 156, please refer to the correct figure. 3. To enhance the manuscript, it would be valuable to provide a detailed explanation of the mechanism of OIL. A pictorial representation and some mathematics would help the readers better understand the concepts. 4. In section 5, you mentioned the idea of an on-chip OIL transmitter, which is a great concept. Please provide recent progress on this topic. If there is no progress, comment on the challenges that are prohibiting it from happening. 5. OIL in visible wavelengths provides a linewidth of around 0.1 nm. Is this narrow enough for coherent VLC? What can be improved? Please comment on that.

6. Your manuscript highlights various applications of OIL in FSO, VLC, and UWOC. It would be beneficial to also include any drawbacks of OIL in these applications and suggest possible approaches to solving them.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

The article gives a comprehensive introduction to the optical injection locking technique. This article is a scoping review therefore, no structured search is reported. The introduction section provides the basic knowledge to understand visible light communication technology.

The manuscript can be beneficial by providing an article selection criterion then the manuscript turns into a less subjective review.

 

As a scoping review, the future trends of optical injection techniques can be expanded and enriched with the personal point of view of the authors. 

Author Response

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Author Response File: Author Response.pdf