Range-Gated LIDAR Utilizing a LiNbO3 (LN) Crystal as an Optical Switch

Round 1

Reviewer 1 Report

In this work, the author designed a range-gated lidar system utilizing LN crystal and sCMOS and analyze the inhomogeneity error caused by the conoscopic interference effect and unideal pulse voltage. They tried to model the inhomogeneity error and proposed a compensation method. Finally, they established an experimental setup to demonstrate it. The current manuscript can not be accepted until they answer the following questions and made some necessary revision.

1.      Most of the figures lost their legends, such as the legends for x and y axis.

2.     The figure caption for Figure. 8 is also lost. A more detail caption for Figure 9 is required to make it more readable.

3.     The authors compared the horizontal pixel distance depth in Fig. 12. I suggest the authors to mark the position in fig.12 that they compared.

4.      For a certain field of view, the total standard deviation is not enough to evaluate the homogeneity of the test results. I suggest the authors to add five local standard deviation including the local standard deviation at four corners and at the middle of field of view. Then, the evaluation results would be more convincing.

The written of the manuscript should be improved. There are a lot of confusion expression and typos, such as “and time it has better imaging performance under specific conditions at the same” in abstract. The “Conscopic interference pattern” should be “Conoscopic interference pattern”.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

 

Review

Title: Range-gated LIDAR utilizing an LiNbO3 (LN)crystal as an op- 2
tical switch

Authors: Chenglong Luan, Yingchun Li, Huichao Guo, Houpeng Sun

Summary: The authors describe the design of a range-gated lidar system based on a LiNbO3 crystal acting as an optical switch.

Comments:

The manuscript is generally well written and I have only a few minor comments:

- line 17: This sentence doesn't make sense.

- Eq. 1: tau_p is not defined in this equation. Did you mean tau_D here?

The quality of the English language in the manuscript is largely ok.

Author Response

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Reviewer 3 Report

The Authors propose a range-gated LIDAR system by using an LN crystal as electro-optical switch and a SCMOS imaging device. The reported results have been numerically and experimentally achieved. Here, my comments to the manuscript:

1.       The main application of the proposed system should be clarified.

2.       The simulation solver should be clarified.

3.       The core of the manuscript is the broadband optical switch. An overview of broadband switch should be reported, aiming at highlighting the main figure-of-merit (see, e.g., Design of a large bandwidth 2× 2 interferometric switching cell based on a sub-wavelength grating. Journal of Optics, 23(8), 085801, 2021; Electro-optic X-switch using single-mode Ti: LiNbO3 channel waveguides. Electronics Letters, 14(19), 553-554, 1983 ; State of the art and perspectives on silicon photonic switches. Micromachines, 10(1), 51, 2019).

4.       The main operation of the system should be clarified.

5.       Section 3.3 should be well organized.

6.       Figure 9.  Please clarify the figure with caption.

 

7.       Please check the English language.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

The manuscript contains some interesting and original results, but the current version has to be rejected and a completely new manuscript may be re-submitted. Our reasons are as follows:

1.       English language of the manuscript is rather bad. We have failed to understand some statements and sentences.

2.       The use of electrooptical switches, and lithium niobate switches in particular, in lidars and range-finders is a standard solution. Meanwhile, the device, explained in the manuscript seems more similar to the range-finder rather than to the lidar. There exist numerous types and variants of such modulators and switches. From the manuscript it is difficult to understand what is the scheme, used by the authors, and why the use of this device makes it possible to use in the lidar the slow and cheap CMOS matrices instead of standard CCD matrices.

3.       At the same time, the comparison of the manuscript with the earlier published paper of the same team in Applied Optics (Ref.[16]) reveals that the section of the manuscript, devoted to the switch performance, to a large extent repeats the said Ref.[16]. So we see or at least suspect some kind of self-plagiarism.

4.       The experimental setup of the prototype of the lidar is explained in a bad manner. We always expect that the paper, considering some optical or laser setup contains the normal drawing of optical scheme with ray tracing and explanation of its optical performance in a step-by-step manner (something like “the radiation is emitted by the laser 1, then it is extended by the telescope 2, then it comes to the beam-splitter 3… etc.”). The photo of the setup (Fig.9) is not informative. Electronics of switching has also to be described in a comprehensive manner.

We do not believe that it is possible to correct the current low-quality manuscript. It would be more reasonable to write the brand-new manuscript and to re-submit it.

No additional comments

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors have addressed all my questions and made necessary revisions. The revised manuscript can be accepted.

Author Response

We are appreciated for your valuable comments，which makes our manuscript better.

Best wishes to you.

Reviewer 3 Report

The Authors have replied to the Reviewer comments. However, the reply to the comment 2 of the 1st revision of the manuscript (The core of the manuscript is the broadband optical switch. An overview of broadband switch should be reported, aiming at highlighting the main figure-of-merit...) is debatable. Besides switching time and ER, the operating bandwidth is a crucial parameter. Therefore, in the overview, the Authors should report also the bandwidth and related references.

Author Response

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Reviewer 4 Report

I am satisfied by the corrections and by the author's answers. The manuscript is ready for publication.

Author Response

We are appreciated for your valuable comments，which makes our manuscript better.

Best wishes to you.