SciPost Submission Page
Adjustable optical isolator based on the resonant optomechanical interaction
by Dong-Yang Wang; Lei-Lei Yan; Cheng-Hua Bai; Qing He; Hong-Fu Wang; Erjun Liang; Shi-Lei Su
Submission summary
| Authors (as registered SciPost users): | Dong-Yang Wang |
| Submission information | |
|---|---|
| Preprint Link: | scipost_202206_00023v2 (pdf) |
| Date submitted: | 2023-02-23 14:30 |
| Submitted by: | Wang, Dong-Yang |
| Submitted to: | SciPost Physics |
| Ontological classification | |
|---|---|
| Academic field: | Physics |
| Specialties: |
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| Approach: | Theoretical |
Abstract
Optical isolators are indispensable in optical information processing tasks and are essential nonreciprocal devices in chiral networks. We propose a proposal to generate an adjustable bidirectional narrow bandwidth optical isolator based on the optomechanically induced transparency in a spinning whispering gallery microresonator. Analyzing the reason for optical isolation, we find that the nonreciprocity of the system comes from the frequency shift induced by the spinning resonator. To maximize the isolation rate, we devise a way to actively modulate the control field to make the desired optomechanical interaction always resonant. So the realized optical isolator is narrow linewidth, which is evaluated via analytical calculation. Moreover, the location of the optical isolator is related to the angular velocity of the spinning resonator. Our proposal provides a promising strategy for designing adjustable nonreciprocal devices expected to facilitate the study of quantum information processing.
Author comments upon resubmission
(1) The direction and location of the optical isolator can be adjusted in our scheme.
(2) The linewidth of the optical isolator is narrow, which helps filter unwanted transmissions and feedback in various optical transmission tasks.
(3) The optomechanically induced transparency is preserved by actively modulating the frequency of the control field.
(4) The realized adjusted non-directional optical isolator can provide flexible options for different optical transmission tasks.
List of changes
The detailed responses are attached as follows, and the main changes are also marked in blue in our revised manuscript.
Q1) Equation (10) is incorrect since it is only valid for the red-detuned case. The authors should correctly define q_s again in Eq. (10).
Reply) Many thanks for your reminder. We have corrected Eq. (10) and added the corresponding descriptions in our revised manuscript. It should be noted that most of the results in our manuscript are discussed in the red-detuned case.
Q2) The authors claimed that the optimal angular velocity is around 800 Hz for optical isolation, and this value depends on the parameters. Is there any way to normalize the value by certain parameters?
Reply) Thanks for your suggestion. We have given a relationship between the optimal angular velocity and the system parameters in Eq. (9) of our revised manuscript. To give a simpler relationship, we recalculate the transmission rate when the system works in the near-resonant region of the red sideband, and please see Eq. (8) in the revised manuscript. So the relationship is only valid for the weak control field case.
Q3) Missing unit for \Omega in Figure 3.
Reply) Thanks for your reminder. We have revised it in our manuscript.
Q4) The authors mentioned that '… where we consider a whispering gallery microresonator coupled to a nearby optical waveguide via the self-adjustment process [36].' I believe Tal Carmon's Nature [47] paper thoroughly studied how a tapered fiber could be stably coupled to a spherical resonator, not this theory paper [36].
Reply) Thanks for your reminder. We have revised the reference in our manuscript.
Q5) The authors can cite another paper experimentally showing optical isolations by Brillouin optomechanics followed by [31] J. Kim, S. Kim, and G. Bahl, "Complete linear optical isolation at the microscale with ultralow loss," Scientific reports 7 (1), 1647, 2017. And can cite the interesting paper demonstrating the suppression of backscattering through the nonreciprocal response by the optomechanical interactions. S. Kim, J.M. Taylor, and G. Bahl, "Dynamic suppression of Rayleigh light scattering in dielectric resonators," Optica 6 (8), 1016-1022, 2019.
Reply) Thanks for your suggestion. We have cited the references in the introduction part of our revised manuscript.
We have carefully checked and revised the English language of our manuscript. Thanks again for your valuable suggestions and comments, which are pretty instructive for our manuscript!
Current status:
Reports on this Submission
Report
In their submission the authors address the question how to realise a "non-directional optical isolator" via optomechanical induced transparency. They propose a pump scheme for an optomechanical system consisting of two cavities and one mechanical oscillator and use standard tools to calculate the transmission amplitudes and isolation ratios.
First of all, the revised submission still contains language oddities, e.g. to propose a proposal. Importantly, I wonder if the authors really mean "non-directional optical isolator" and not "directional" or "non-reciprocal" which would make more sense to me.
I found the literature review to be partially inaccurate in important places, e.g. Ref. 40-42 are cited for "proposals" whereas all three papers actually reported experiments!
The theoretical analysis given in this submission (Eq. 3 to 6) is absolutely standard. The only result that is new, at least in the current form, is Equation (7), and closely related Equation (8). These quantities are then shown/discussed in Figure 3 through 5.
The reader is told that the narrow bandwidth of the proposed isolator will be an asset but of course signals have finite bandwidth and a very narrow filter is not useful in practice. The device has to fit its purpose.
In my opinion the reported results, though they are likely technically correct, are not significant enough to warrant publication in any of the SciPost journals.