Optical Fibers Use in On-Chip Fabry–Pérot Refractometry to Achieve High Q-Factor: Modeling and Experimental Assessment

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

1. line 75, what do the authors mean by resonating waveguide? Waveguides are not resonant structures and how can they be resonating?

  2. line 109, FRL appears for the first time here, and therefore should not be abbreviated.   3. line 120, this sentence is unclear. no matter what kind of fiber, their interface are alway consist of core and cladding materials. The authors should clarify what they mean here for the lensed fiber and what is the difference.   4. line 130, this sentence ("work around can be...") is grammarly unclear, please modify it.   5. line 131-132: this sentence is too general, and delivers no real information. What changes in "some structures" can be engineered? Please specify and illustrate.
  6. line 210, the beam inside a resonator, in this case FP cavity, cannot be described as "resonate through", please change.   7. line 216: how large is the device bandwidth? is it only 6 nm? Can the author discuss about the bandwidth limitation with the design of the FP mirrors, FRL and fibers?   8. line 241: is the sensitivity tested or simulated? Please be very accurate and differentiate data that is simulated from actual tested, to avoid confusion.   9. line 264: Thorlabs, not Thorlab   10. line 295: typo error, remove "This"   11. It is hard to draw the conclusion using one resonance for the Q, the authors should do an average Q/linewdith extraction to calculate the Q for fundamental and higher order modes.   12. Also, when describing the Q enhancement, since it is relatively a small number, the author should use percentage to describe how much does the Q improved with cleaved fiber. Comments on the Quality of English Language

NA

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This manuscript reports on the simulated and experimental results of single-mode fibers (SMF) in different geometric structures to enhance light confinement and Q-factor within on-chip FP resonators. The presented designs and tested results are encouraging and could be helpful towards further development in related application fields. The manuscript can be further improved upon the following suggested modifications.  

1.     Does there exist an optimal design for the parameters of the upright lenses and FRLs for the structure in Figure 1d? Can the authors work out the optimal structural parameters and performance for the tested SMF-28-J9 in the Figure 1d design, and compare them with the achieved experimental results?

2.     In Fig. 5, it is clearly seen that both fiber facets are angle cleaved. Can the authors evaluate the dependence of the coupling loss and Q-factor upon this angle-cleaving effect?

3.     At the beginning of the third section, Results and Discussion, the first sentence, “This The experimental investigation…” needs to be modified.

The manuscript would be suitable for publication in this journal upon the above-mentioned modifications.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

This is in response to the points in my 1st review report:

1. Thank you for your explanation. Like what you showed in the reference, the resonating structure is the retro-reflector. Therefore, to avoid confusion, I suggest changing line 75 from "resonating waveguide" to "resonating structure"

7. Thank you for the detailed illustration. Can the authors include the explanation into the manuscript? It is a really good explanation and should be implemented into the discussion.

8. Please change line 241 from "The sensitivity is tested using blood..." to "simulated"

Author Response

Comment 1: [1. Thank you for your explanation. Like what you showed in the reference, the resonating structure is the retro-reflector. Therefore, to avoid confusion, I suggest changing line 75 from "resonating waveguide" to "resonating structure"]

Response 1: Thank you for your care to avoid ambiguity. We modified it as suggested and included the new one in the modified manuscript.

Comment 2: [7. Thank you for the detailed illustration. Can the authors include the explanation into the manuscript? It is a really good explanation and should be implemented into the discussion.]

Response 2: Your concern is highly appreciated. You may kindly find the explanation added to the modified manuscript.

Comment 3: [8. Please change line 241 from "The sensitivity is tested using blood..." to "simulated"]

Response 3: To avoid confusion, we modified it as suggested, and included the new one in the modified manuscript.