Experimental Proof-of-Concept of a Spatial Photonic Switch Based on an Off-Axis Zone Plate in Millimeter Wavelength Range

Round 1

Reviewer 1 Report

An experimental demonstration of engineering a multichannel optical switch based on a dielectric mesowavelength diffraction element with broken geometric symmetry (off-axis Wood zone plate) has been provided in this manuscript. This result is based on a previously published theoretical prediction. The manuscript is well written and logically presented.

 

Provided the scalability of these results to another wavelength ranges, this work is of particular interest to the photonics community. I am happy to recommend the manuscript for a publication, however, some minor issues with the presentation of the results might be fixed before publishing:

1. Figure 3: it still might be better to split the panel into 3 different panels for each frequency so that it would be clear that indeed beams are spatially separated. The current appearance of the figure is a bit confusing, despite the clear caption.
2. Figure 4: the legend explaining which curve corresponds to which frequency will be helpful. 

Author Response

Response to the 1st Reviewer

Dear Reviewer,

Thank you very much for your review and thoughtful comments!

All editions are marked in red in the manuscript.

 

• "Figure 3: it still might be better to split the panel into 3 different panels for each frequency so that it would be clear that indeed beams are spatially separated. The current appearance of the figure is a bit confusing, despite the clear caption."

The Figure 3 and its legend have been changed.

• "Figure 4: the legend explaining which curve corresponds to which frequency will be helpful."

The Figure 4 and its legend have been changed.

Reviewer 2 Report

The Authors propose a full-optical wavelength-selective dual-channel switch based on the photonic hook effect. The reported results have been experimentally achieved.  Although the results are promising for the next generation programmable photonics, a major revision of the manuscript is suggested to address the following comments:

 

-          In the Introduction Section, the literature on the photonic switches should be enlarged to help reader in the manuscript rating, including recent microphotonics devices (e.g. Design of a large bandwidth 2× 2 interferometric switching cell based on a sub-wavelength grating. Journal of Optics, 23(8), 085801, 2021), Micro Electro-Mechanical Systems (MEMS) switching matrices (e.g. MEMS optical switches. IEEE Communications magazine, 39(11), 158-163, 2001.), LiNbO3-based switches (e.g. Electro-optic X-switch using single-mode Ti: LiNbO3 channel waveguides. Electronics Letters, 14(19), 553-554, 1983.), III–IV-based switches (e.g. Low-driving-current InGaAsP photonic-wire optical switches using III-V CMOS photonics platform. Optics Express, 20(26), B357-B364, 2012.) , semiconductor optical amplifier switching matrices (e.g. SOA gate array recirculating buffer for optical packet switching. In Optical Fiber Communication Conference (p. OWE4). Optica Publishing Group., 2008) liquid crystal-based switches (e.g. Realisation and characterisation of a ferroelectric liquid crystal bistable optical switch. Molecular Crystals and Liquid Crystals, 372(1), 353-363., 2002), all-optical switches (e.g. All-optical switches on a silicon chip realized using photonic crystal nanocavities. Applied Physics Letters, 87(15), 151112, 2005).

Moreover, to rate the device performance, an overview of the potential applications, with relative requirements, should be provided.

-          In the Section II, the design of the used devices should be discussed. In particular, the design of the photonic devices features should be provided.

-          The photonic switches are usually classified according to the crosstalk, insertion loss, bandwidth and so on. Please, report these parameters, also comparing them with the state-of-art.

Author Response

Response to the 2_nd Reviewer

Dear Reviewer,

Thank you very much for your review and thoughtful comments!

All editions are marked in red in the manuscript.

• "In the Introduction Section, the literature on the photonic switches should be enlarged to help reader in the manuscript rating,..."

Required references added to the Introduction section. All the changes are highlighted in red.

• "In the Section II, the design of the used devices should be discussed. In particular, the design of the photonic devices features should be provided."

Relevant changes have been made to the text and highlighted in red.

• "The photonic switches are usually classified according to the crosstalk, insertion loss, bandwidth and so on. Please, report these parameters, also comparing them with the state-of-art."

The parameters of the proposed switch are discussed in more detail. Changes are highlighted in red.

Round 2

Reviewer 2 Report

The Authors have modified the manuscript according to the Reviewer suggestion. Therefore, I suggest the manuscript publication.