Compact On-Chip Metalens-Assisted Optical Switch Enabling Efficient and Scalable Beam Switching

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this paper, the authors propose and demonstrate an integrated optical switch that leverages an optical phase array (OPA) and an on-chip metalens. The authors do not clearly explain the application and final purpose of the research, making it difficult for readers to understand the relevance and impact of the work, as well as the potential benefits and practical applications. Although the results presented are consistent, there is no comparison with state-of-the-art solutions (see other technologies, as Design of a large bandwidth 2× 2 interferometric switching cell based on a sub-wavelength grating. Journal of Optics, 23(8), 085801, 2021;  Applications of optical MEMS for space missions. In Proc. 7th ESA Round Table on Micro/Nano Technologies for Space (pp. 13-7). ESA/ESTEC, 2010) . This makes it difficult to assess the real significance and progress of the research. It is essential to provide a detailed comparison with the relevant literature to establish the contribution and effectiveness of the proposed solution. Furthermore, the English used is too simple and lacks the technical precision expected in a scientific manuscript.

Here,there are my comments:

· Explaining what a thermo-optic effect (line 71) is consistent with the precision and attention dedicated to writing the introduction. It is often useful to describe and explain the physical principle in order to provide the reader with as much technical information as possible.

· The authors should justify the choice of the operating wavelength of 1550 nm in line 166.

· In Figure 1, the coordinate axes are incorrect.

· As already stated, the authors should improve their English. For example, on line 107, what does "To scrutinize?" mean? Wouldn't it be better to say "to examine"?

· In line 118-119, the authors should describe in detail the methods used to perform thermal simulations using Ansys/Lumerical software

· In line 120, why 100 mW?

· Lines 131-133: Is there a theoretical physical relationship underlying this consideration?"

· The authors should explicitly state and explain what they mean by "theoretical predictions" in line 169

· The conclusions offer a comprehensive summary of the results obtained and the implications of the research. However, it is recommended to further expand the discussion of the results to include a cristical assessment of the study’s limitations and possible future directions for research.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors In this manuscript, authors propose and demonstrate an integrated optical switch that leverages an optical phased array (OPA) and an on-chip metalens, highlighting its potential for efficient and scalable beam switching across multiple ports within a compact footprint. The on-chip metalens, characterized by varying slot lengths, performs wavefront manipulation of the fast Fourier transform function, resulting in beam deflection with a focusing length of 20 µm. Simulated validation of the proposed optical switch demonstrated efficient beam deflection, yielding a 1 × 8 beam switching with a compact design. The subject of the paper is interesting. However, here are some problems need to be addressed. 1. The English writing should be improved, there are some errors. 2. More details about simulation should be given, for example, what kind of boundary conditions, what kind of light source. 3. It should be detailed that how to fabricate the proposed metalens structure. 4. What is the advantage of the proposed lens compared with previous other ones? 5. For discussing the graphene and lens, the authors are suggested to cite the following papers for enriching background: Nano Letters 2023, 23, 23, 10991-10997; Laser & Photonics Reviews, 2300729,2024.

 

 

 

 

 

 

Comments on the Quality of English Language In this manuscript, authors propose and demonstrate an integrated optical switch that leverages an optical phased array (OPA) and an on-chip metalens, highlighting its potential for efficient and scalable beam switching across multiple ports within a compact footprint. The on-chip metalens, characterized by varying slot lengths, performs wavefront manipulation of the fast Fourier transform function, resulting in beam deflection with a focusing length of 20 µm. Simulated validation of the proposed optical switch demonstrated efficient beam deflection, yielding a 1 × 8 beam switching with a compact design. The subject of the paper is interesting. However, here are some problems need to be addressed. 1. The English writing should be improved, there are some errors. 2. More details about simulation should be given, for example, what kind of boundary conditions, what kind of light source. 3. It should be detailed that how to fabricate the proposed metalens structure. 4. What is the advantage of the proposed lens compared with previous other ones? 5. For discussing the graphene and lens, the authors are suggested to cite the following papers for enriching background: Nano Letters 2023, 23, 23, 10991-10997; Laser & Photonics Reviews, 2300729,2024.

 

 

 

 

 

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In this manuscript, authors mainly study the on-chip integrated optical switch consisting of MMI, PM array, metalenses layer, and waveguide array. The results show that the switch can effectively switch beams between different ports. In the simulation work, the authors conducted extensive computational analyses to design and verify the performance of the integrated optical switch, which provides critical data support and theoretical guidance for the experimental realization, validates the effectiveness of the integrated optical switch design, and offers references for its performance optimization in practical applications.

I would recommend the article to be accepted with minor revisions. My comments for the author are as follows, 

1. Suggest the author consider studying the performance changes and compensation mechanisms of integrated optical switches at different temperatures, as the thermal optical phase modulator may be affected by environmental temperature changes;

2. In comparative analysis, it is recommended that the author include comparative analysis of experimental results with peers;

3. Pls provide a detailed introduction of experimental processes, including the instruments and equipment used.

 

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Editor,

In this manuscript, an optical switch based on wave interference is designed, which can direct 1550 nm wavelength light to 4 to 16 output ports. This work needs major revisions to improve its quality. The proposed comments are listed below.

1. In the metalens section, how is the light selected in different directions? Explain physically.

2. In Figure 2c, it seems that for powers close to 100 milliwatts, non-linear effects occur while they are ignored and the behavior of the curve is linear.

3. In Figure 3e, what is the vertical axis? Why is its value more than 1? Is it normalized?

4. The performance of the switch is just a simulation and not compared with any data? How do we confirm their correctness?

5. To better evaluate the performance of the proposed switch, it is better to present a table and compare the results of this work with other works.

6. What is the response speed of the switch? What is the appropriate wavelength range?

7. Physically explain what change in the slot dimensions changes in the signal transmission.

 

Kind regards,

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The Authors have modified the manuscript according to the Reviewers' suggestions.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Editor,

The comments have been addressed so I recommend the manuscript for publication. Finally, I suggest the "reference" column of table 1 be shifted to the first column.

Kind Regards,