Compact and Ultra-Broadband 3 dB Power Splitter Based on Segmented Adiabatic Tapered Rib Waveguides

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The authors proposed a novel structure inspired by the segmented tapered edge coupler to realize a 3-dB power splitter that combines broadband, compactness, and good manufacturability. The optimal design was attempted and experimentally shown.
The design approach and calculations are scientifically valid, and the results are sufficiently novel and impactful.
Therefore, this paper could be published in this journal.
However, I found a typo “porposed” in line 169. 

Author Response

Thank you for pointing this out. We agree with this comment. We have corrected the mistake of “porposed” in line 169. Please refer to page 6, line 191 in the revised manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

The Authors present a compact and ultra-broadband 3 dB power splitter based on segmented adiabatic tapered rib waveguides, with a length of 23.4 μm, as well as a Mach-Zehnder modulator (MZM) implemented for validation purposes. Both experimental and simulated results are provided. The manuscript addresses an interesting and relevant topic in the field of integrated photonics. However, several aspects require clarification or improvement before the manuscript can be considered for publication. My detailed comments are as follows:

 

1. A significant emphasis is placed on the edge coupler design, which serves as the basis for the proposed 3 dB splitter. Since this component will also be used for fiber-to-chip coupling, the manuscript should include a brief overview of state-of-the-art edge couplers (see, e.g., Silicon nitride spot size converter with very low-loss over the C-band. IEEE Photonics Technology Letters, 35(22), 1215-1218, 2023; Fiber-chip edge coupler with large mode size for silicon photonic wire waveguides. Optics express, 24(5), 5026-5038, 2016). This would help justify the design choices and clearly indicate the novelty or advantages of the proposed structure compared to existing approaches.

 

2. The authors are encouraged to specify the loss values assumed when computing the splitting ratio. It is essential to clarify whether these losses are estimated from simulations, experimental data, or a combination of both, and how they might affect device performance in practical scenarios.

 

3. While broadband performance is highlighted as a key feature, the manuscript lacks a quantitative comparison with similar broadband couplers reported in the literature. A comparative analysis—both in terms of bandwidth and insertion loss—would provide a clearer picture of how this work advances the state-of-the-art (see, Design of a large bandwidth 2× 2 interferometric switching cell based on a sub-wavelength grating. Journal of Optics, 23(8), 085801, 2021; Polarization-insensitive optical switch on silicon-on-insulator platform. Optics Express, 26(11), 14340-14345, 2018). Additionally, the relevance of broadband behavior should be contextualized with respect to specific applications (e.g., WDM systems, quantum photonics, etc.).

 

4. The manuscript reports the fabrication of a Mach-Zehnder Modulator in addition to the splitter. The authors should explain why a push-pull configuration was selected for the MZM. Is this choice motivated by performance optimization (e.g., modulation efficiency, linearity), fabrication constraints, or compatibility with the splitter design? A brief discussion would enhance the completeness of the work.

Author Response

Thanks for your comments and suggestions. Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The Authors have modified the manuscript according to the Reviewers suggestions.