Correlated Photon Lidar Based on Time-Division Multiplexing

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper introduces a time-division multiplexing-based correlated photon lidar system aimed at addressing the challenges faced by traditional single-photon lidar (SPL) systems, particularly in noisy environments. The proposed system utilizes narrowband pulsed lasers with fixed and stable delays, combined with intensity variations to achieve temporal and intensity correlations. Additionally, the paper introduces an adaptive cross-correlation method and a time-slicing technique to extract weak signals from noisy environments effectively. Experimental results demonstrate successful detection at a range of 1.5 km under high-noise daytime conditions, emphasizing the system's robustness, cost-effectiveness, and potential for practical applications.

The article is mostly well-written but occasionally verbose, with minor redundancies. Some technical descriptions can be streamlined for clarity. As such the presented material qualifies to be published in Photonics. However, a few questions remain, and clarifications and corrections should be applied in a revised version of the manuscript prior to publication:

 

MA:

1)     The study focuses on a single experimental distance (1.5 km), which limits the generalizability of the results to other ranges or scenarios. Limited exploration of diverse environmental conditions beyond intense daytime noise.

2)     While the paper claims advantages over traditional SPL systems, it lacks a detailed quantitative comparison with state-of-the-art alternatives in terms of performance metrics like cost, detection accuracy, and real-time performance.

3)     The potential challenges in transitioning this laboratory system to real-world deployment (e.g., robustness to hardware misalignment) are not addressed in detail.

4)     We have seen lots of study on time/frequency-multiplexing techniques, what is the novelty of this study? This issue should be addressed more clearly.

a)        Wu D, Zheng T, Wang L, et al. Multi-beam single-photon LiDAR with hybrid multiplexing in wavelength and time[J]. Optics & Laser Technology, 2022, 145: 107477.

b)        Zang Z, Li Z, Luo Y, et al. Ultrafast parallel single-pixel LiDAR with all-optical spectro-temporal encoding[J]. APL Photonics, 2022, 7(4).

 

Minor:

1)     Line 57, "…we propose a time-slicing method for individual measurements." Change "propose" to "proposed" for consistency with past tense.

2)     Use consistent formatting for technical terms, e.g., "time-division multiplexing" vs. "Time Division Multiplexing."

Author Response

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Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The manuscript proposes a time-division multiplexing-based correlated photon lidar system, which is able to address the challenges of background noise interference and system complexity in single-photon lidar (SPL). However, minor revisons are required.

1) Please provide a comparative work with with other existing methods in terms of key metrics such as signal-to-noise ratio improvement, detection range extension, and accuracy enhancement.

2) In-depth analysis about the sources of errors, such as laser pulse jitter, detector noise characteristics, and environmental factors. Besides, it is also benefical for providing some methods or strategies to estimate and mitigate these errors.

3) Please give more detailed information about the detection part, such as, SPAD sensor type, arrays size, pixel size, and also pitch, etc. This is also helpful for increase the credibility of the results.

4) It is highly recommended that authors should cover more recent and related studies in the field, which  This would help to highlight the novelty and significance of this work.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

In this manuscript, a time-division multiplexing-based correlated photon lidar system is proposed. The proposed system provides both temporal and intensity correlations in the signal. Moreover, an adaptive cross-correlation method combined with time slicing is developed to extract histogram signals. Experimental results show that the anti-noise capability of this proposed system is effectively enhanced, facilitating rapid and continuous detection. The research result provides valuable insights into the photon lidar. Overall, This research is original and interesting. This study is beneficial for researchers in the field of photonics. I recommend publication after following minor revisions:

1. The abstract is too long, it is recommended to streamline it.

2. Can the authors further enrich the experimental results? At present, the experiment is not deep enough and systematic enough.

3. My personal suggestion is to compare the experimental results with the theoretical simulation results.

 

Author Response

Please see the attachment.

Author Response File: Author Response.docx