loading noise

[indayara]

2 questions: 1- How could I model a transmission back to back with Gnpy? Recently, I modelled a span with Gnpy to work in back to back : Tx+ROADM+Rx, but the OSNR penalty in reception was higth (Tx_OSNR= 40dB and in Rx_OSNR =30dB) . I'm looking for ideas.... 2- How can I add a source noise in the span to measure the OSNR_limit?

[jktjkt]

Can you share the input file(s) that you're using? What numbers are you getting, and what are the expectations?

Generally speaking, the transponder's Tx OSNR is taken from the tx_osnr parameter of the chosen mode of the transponder in the equipment library. When running gnpy-transmission-example, there's a "gotcha" in that the first mode of the first transponder type gets picked. The network is also always modeled with a "full spectrum load" (i.e., worst case conditions, not just a single channel transmission). The spectrum is described in the SpectralInformation structure in the input JSON file with the network topology. Our defaults propagate 76 channels aligned on a 50 GHz grid.

We're working on making these assumptions and hidden steps more visible. In the meanwhile, if you can let us know more about what you're modeling, we'll be happy to help.

[indayara]

Hi Jan,

Thank you for your feedback.

I'm trying to realize 2 test.

First Test:

• Back to back transmission (tx->Rx)

Second test: -Tx->roadm->10spans+edfas+roadm+loading noise->rx See the schedule in attached - pptx file. I would like to obtain the following results: a graph (powerperchannel vs OSNR_limit). My doubt is: how can I add a loading noise block in the gnpy model. In real experiments, normally we add a loading noise block to obtain the OSNR limit in a transmission , thus we can obtain the results as: transmission penalties vs power per channel or distance etc. In attached I send gnpy files. Let me know how to build a gnpy model for back to back transmission too.

Thank you in advance, Indayara.

On Mon, Sep 21, 2020 at 6:29 PM Jan Kundrát [email protected] wrote:

Can you share the input file(s) that you're using? What numbers are you getting, and what are the expectations?

Generally speaking, the transponder's Tx OSNR is taken from the tx_osnr parameter of the chosen mode of the transponder in the equipment library https://gnpy.readthedocs.io/en/master/json.html#transceiver. When running gnpy-transmission-example, there's a "gotcha" in that the first mode of the first transponder type gets picked. The network is also always modeled with a "full spectrum load" (i.e., worst case conditions, not just a single channel transmission). The spectrum is described in the SpectralInformation https://gnpy.readthedocs.io/en/master/json.html#spectralinformation structure in the input JSON file with the network topology. Our defaults propagate 76 channels aligned on a 50 GHz grid.

We're working on making these assumptions and hidden steps more visible. In the meanwhile, if you can let us know more about what you're modeling, we'll be happy to help.

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-- *Indayara Bertoldi Martins * Ph.D Electrical Engineer Mobile: +55 11 986868726 e-mail: [email protected] or [email protected] Skype: Indayara B Martins