Numerical Study of Resonant Optical Parametric Amplification via Gain Factor Optimization in Dispersive Microresonators

Round 1

Reviewer 1 Report

In this manuscript, the authors present a numerical study on optical parametric amplification process in a few micrometer-long dispersive microresonator. It was carried out by solving the wave equation in parallel with the nonlinear equation of electron cloud motion (or polarizability) of a gain medium, by using the finite difference time domain method. Therefore, authors claimed that it is possible to achieve a wideband high-gain optical amplification in a dispersive micro-resonator which has more resonance frequencies that yield an optical gain resonance.

 

Optical parametric amplification OPA in microscale indeed is a important topic of interest for many fields, especially for integrated nonlinear photonic. It maybe that this will ultimately be a paper worthy of publishing but as it stands, the manuscript will need to be improved prior to recommendation for publication. As the author’s paper are focus on the OPA in microscale device, they should cite the following relevant and important references, which reflect the most current results and direction in this field:  

Luo et al., “Optical Parametric Generation in a Lithium Niobate Microring with Modal Phase Matching”, Phys. Rev. Applied 11, 034026 (2019) Sua et al., "Ultra-wideband and high-gain parametric amplification in telecom wavelengths with an optimally mode-matched PPLN waveguide," Opt. Lett. 43, 2965-2968 (2018) Chen et al., "Ultra-efficient frequency conversion in quasi-phase-matched lithium niobate microrings," Optica 6, 1244-1245 (2019)

 

Some major comments:

For the parameters used in the numerical simulation such as the resonance frequency, damping coefficient, atom density, and atomic diameter. The author should suggest some material for microscale device fabrication which are relevant with the result presented, for example Aluminum nitride, lithium niobate, etc. What is the unit of the amplification plot given in fig 5, 7 , 8, 9, 10? Dispersive medium also means that the temporal walk-off between interacting waves, which limits the effective interaction length and gain? What is the solution to overcome this and achieving high gain? Especially the author claimed that dispersive micro-resonator gave more optical gain resonances. Dispersive medium also like to induce break down of high peak power pump pulse, is this considered in the simulation? The author mentioned the cavity should be low loss. A recommended maximum loss should be given. For instance, how does it compare to the state-of-art result given in the Chen et al., "Ultra-efficient frequency conversion in quasi-phase-matched lithium niobate microrings," Optica 6, 1244-1245 (2019)? The author should include some of the potential applications that are relevant to the presented results.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Report on manuscript photonics-640648 Asirim:

In the manuscript entitled "numerical study of resonant optical parametric amplification via gain factor optimization in dispersive microresonators" by Asirim and Kuzuoglu, the authors have carried out an extensive numerical investigation on achieving wideband, high-gain optical parametric amplification in a dispersive microresonator. Their method started with solving the coupled wave equation along with the nonlinear equation of motion of the electron cloud for a nonlinear dispersive medium. Alternatively, the system is modeled as a driving nonlinear harmonic oscillator. Since the numerics highly depends on the boundary conditions, by assuming certain boundary conditions, the authors then numerically solved the coupled nonlinear equations for different cases.

After carefully reading the manuscript, I found the results are highly technical and insignificant. The work is poorly organized and presented, which brings much difficulty to access the content.

When asked, however, whether I would recommend it for Photonics, I do have the following reservations:

(1)  The physics is unclear and ambiguous. I strongly suggest that in the revision, such ambiguity of the physics could be resolved.

(2)  The poor organization should be improved. Although the authors provided tens of figures produced from numerics, yet in the text most of them are barely referenced and some of them are even never mentioned. In the revision, please add the missing information on those figures.

(3)  The tables were lack of explanations in the content. In the revision, further interpretations on these tables should be provided or enlarged.

(4)  Minor suggestions: There are grammar issues in the text.

Author Response

Please see the attachment

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

In their reply and resubmitted manuscript, the authors have addressed my concerns on major flaws or shortcomings of the presented numerical study.
Thus, I believe that the current manuscript is scientifically valid and technically sound for publication in Photonics.

Reviewer 2 Report

The authors have made necessary revision according to my previous report and have addressed the issues identified previously. The revised manuscript looks better now. Although the presentation could be further improved, especially the tens of formulas, I could support its consideration in Photonics.