Compact Quantum Random Number Generator Based on a Laser Diode and a Hybrid Chip with Integrated Silicon Photonics

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

See the attached file.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

English Language should be polished.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

The authors of the manuscript ”Compact quantum random number generator based on a laser diode and silicon photonics integrated hybrid chip” proposed and experimentally tested a compact and low-power-consumption quantum random number generator (QRNG) based on a laser diode and silicon photonics integrated hybrid chip. From an experimental standpoint, the research is quite well-conducted and the results appear promising. However, the paper requires further attention and revision, particularly in the area of theoretical entropy estimation.

The most concerning aspect of the presented manuscript pertains to Equation 16, as it may not be the appropriate formula for the worst-case scenario. This equation has significant limitations, as outlined by the authors of the referenced paper. Therefore, the entropy estimation requires more careful consideration and warrants additional discussion and justification.

Additionally, the paper contains some flaws and typos, which could be easily corrected with a careful review.

Despite these areas for improvement, I believe that the paper has the potential to make a valuable contribution to the field and should be recommended for publication after the necessary revisions have been made.

Comments on the Quality of English Language

the paper contains some flaws and typos, which could be easily corrected with a careful review.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 3 Report

Comments and Suggestions for Authors

Random numbers are key resources in the information age. They play an essential role in various applications, such as simulation, cryptography, and fundamental physical experiments. Utilizing photonics integration technology to develop a chip-level Quantum Random Number Generator (QRNG) shows promise as a cost-effective approach. However, a major challenge arises from the inability of a single material to integrate light sources, and detectors simultaneously. A viable solution involves integrating individual devices using hybrid integration techniques to achieve a chip-level QRNG.

 The manuscript proposed and experimentally verified a compact and low-power-consumption quantum random number generator (QRNG) chip based on vacuum noise scheme with hybrid integration technology. The hybrid chip’s size is 8.8×2.6×1 mm³, and a common mode rejection ratio greater than 40 dB for integrated homodyne detection was achieved. There is no need of the additional balancing technology. A precise noise model is presented, so the experimental results are consistent with the theoretical analysis well. Several microwatts LO power can generate a quantum-to-classical noise ratio greater than 10 dB. The total power of entropy source is 80 mW. The proposed QRNG has the potential for use in scenarios of moderate MHz random number generation speed, with low power, small volume, and low cost prioritized. Overall, I recommend its publication. 

Author Response

We thank the referee for the valuable recommendation.

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Author,

 

I like the paper with the title "Compact quantum random number generator based on a laser diode and silicon photonics integrated hybrid chip". It is very interesting topic. The overall of the paper is perfect and I have just a minor comments.

It would be valuable if you highlight the extent to which size you can decrease the size of the chip and the experimental challenges that this improvement addresses. 

Best regards,

 

 

Author Response

       We thank the referee for the valuable recommendation. The length, width and height of the silicon photonics chip are 5 mm, 2.5 mm and 0.5 mm respectively. This is also the size of half block of CUMEC CSiP180Al multi-project wafer technology. The chip is multiplexed used for other uses. According to the utilized devices, the size of silicon photonics chip can be reduced to about 1×0.5×0.5 mm³ in principle. For packing easily, the width should be tuned to 2 mm. Then the whole size is tuned to 1×2×0.5 mm³. The length of mount 1 can be reduced to the length of laser chip. Thus the hybrid chip’s length can be reduced to about 2 mm. Then the packaged hybrid chip can be reduced to about 2×2×1 mm³. The main experimental challenge is packing such small devices, especially along the width direction. When the width is short, the droplets of ultraviolet glue may pollute the laser chip. Thus the width of silicon photonics chip is tuned from 0.5 mm to 2 mm for feasible packing.

     We have added above paragraph in the manuscript (lines 113-123).

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I am satisfied with the revised manuscript. I can recommend its publication.

Comments on the Quality of English Language

No comments on the quality of English Language.