200 Gbps/λ PON Downstream C-Band Direct-Detection Links with ≥29 dB Power Budget
, Pablo Torres-Ferrera 1, Giuseppe Rizzelli 1,2,*, Roberto Mercinelli 3, Valter Ferrero 1 and Roberto Gaudino 1Round 1
Reviewer 1 Report
The authors should discuss widely the degree of novelty in comparison with previous works (it could be seen as an extension of the paper [17] but using PAM-8 in simulation). Besides, authors should add a discussion about considerations, requirements, and limitations to carry out the experimental setup as well as a commercial solution.
Minor suggestions: Briefly extend the explanation or discussion of the following:
- Operation/Similarity of SQRT over POLY
- Operation/performance of VNLE
- Number of taps for each equalizer
- Lines 222-223 “In addition to the modulation nonlinear effect and the fiber Kerr nonlinear effect, the nonlinearity caused by the interaction between chromatic dispersion and DD can be mitigated by using the SQRT technique”
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this work, the authors show, through simulation results, the feasibility of a 200 Gbit/s per wavelength PAM-8 PON downstream connection, with a maximum 20 km fiber length in the C-band and direct-detection. The paper is well-written and the scientific description of the simulation setup and the results obtained seem well addressed.
The authors should provide a more detailed explanation:
- why they have chosen to use the C-band, instead of the O-band, when the two latest PON standards have used this band for downstream transmission, and also because the use of the O-band avoids the need for chromatic dispersion pre-compensation;
- why they have decided for 8-PAM, instead of 4-PAM, when this latter is more common;
- on the possibility of using coherent detection, instead of direct detection, for the 200G solution
- on the generation of the I and Q components after the FIR filters and how the I/Q modulator is driven should be provided
In the attached file, you can find my revision comments.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
In this manuscript, the authors demonstrated a 200-Gbps downstream communication over 20 km SMF using PAM-8 modulation and direct detection, in which a power budget no less than 29 dB was achieved. The authors compared the performance of 3 DSP options in the receiver. The results are clear and adequate to support the conclusions. In my opinion, this investigation is meaningful to the design of high-capacity PON transmission system. The paper can be considerd for publiscation in Applied Sciences. There are two issues provided for the authros.
- The simulation software is not clearly described. Is it a commercial software or a homemade software? If it is a homemade one, the authors should give more detailed information to show its reliability.
- The authors of Ref. 2 should be checked.
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
The author presents a study of the simulative analysis of a 200 Gbps per
wavelength (λ) 8-level pulse amplitude modulation in a optical communications systems.
In general communication is of interest and provides simulation results that must be taken into account. But we consider that the method they use based on chromatic dispersion digital pre-compensation and Quadrature Mach-Zehnder Modulation at the optical line termination must be explain in deep detail from a physical point of view.
¿Whats is the total optical signal noise ratio in the system and how to calculate in the simulation with the crosstalk between channels?
Author Response
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Author Response File: Author Response.pdf
