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  • About QAM in the fibre optical

    From Michel@21:1/5 to All on Wed Mar 20 01:42:19 2019
    Bonjour,

    A big hello to Huub for all these valuable words.

    For the fibre opticals :

    (1) I understood that RZ line coding is not used today, nor by IEEE, nor IUT-T.

    (2) Common line codings are NRZ and PAM4. But is there an IUT-T recommandation or a text that introduced QAM in the fibre opticals?

    We have perhaps QAM-16, but not QAM-64. It seems that QAM is not used for optical fiber in 802.3.

    Thousand thanks,
    Michel

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  • From Michel@21:1/5 to All on Wed Mar 20 03:06:33 2019
    Huub,

    I just find some information in G.Sup39 (02/2016).

    Best regards,
    Michel

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  • From Huub van Helvoort@21:1/5 to You on Tue Mar 26 13:28:34 2019
    Bonjour Michel,

    You wrote:

    Huub,

    I just find some information in G.Sup39 (02/2016).

    Best regards,
    Michel

    I am glad you found it yourself ;-D

    Kind regards, Huub.


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  • From arstpt.michelh@gmail.com@21:1/5 to All on Thu Mar 28 03:48:54 2019
    Bonjour Huub,

    I remark there is no specific recommandations about line coding for OTN.

    It seems that QAM is only used in DWDM. We can see that in : draft-ggalimbe-ccamp-flex-if-lmp-07

    (for LMP) "Modulation format: indicates the Transceiver capabilities
    to support a single or multiple modulation format like:
    BPSK, DC-DP-BSPSK, QPSK, DP-QPSK, QAM16, DP-QAM16,
    DC-DP-QAM16, 64QAM".

    Have you, please, an advice for this subject ?
    Thousand thanks,
    Michel

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  • From Huub van Helvoort@21:1/5 to All on Fri Mar 29 10:28:29 2019
    Bonjour Michel,

    You reply:

    I remark there is no specific recommendations about line coding for OTN.
    Did you look at G.959.1 and G.698.2?

    It seems that QAM is only used in DWDM.

    OTN on the optical fiber uses the same modulation as DWDM.
    The difference between OTN and DWDM is visible at the digital
    content (bits and bytes).

    Have you, please, an advice for this subject ?

    I hope it is clear now.

    Best regards, Huub.


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  • From Michel@21:1/5 to All on Sat Mar 30 08:18:11 2019
    Bonjour Huub,

    Did you look at G.959.1 and G.698.2?

    Perhaps, I read these recommandations too quickly. Thank you for your recall.

    G.959.1 notes NRZ, RZ, and PAM4 (for 50 Gbit/s), but not QAM.
    G.698.3 notes NRZ, and DP-DQPSK (for 100 Gbit/s), but not QAM

    OTN on the optical fiber uses the same modulation as DWDM.
    The difference between OTN and DWDM is visible at the digital
    content (bits and bytes).

    I keep in mind this statement.

    There is not yet indication of 16-QAM for OTN (amplitude modulation together with phase modulation). There is only amplitude modulation, or only phase modulation.

    I hope it is clear now.

    It begins !

    Best regards, Michel

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  • From Huub van Helvoort@21:1/5 to All on Sat Mar 30 16:33:41 2019
    Bonjour Michel,

    Did you look at G.959.1 and G.698.2?

    Perhaps, I read these recommandations too quickly. Thank you for your recall.

    G.959.1 notes NRZ, RZ, and PAM4 (for 50 Gbit/s), but not QAM.
    G.698.3 notes NRZ, and DP-DQPSK (for 100 Gbit/s), but not QAM

    You are right. I was looking at contributions proposing to add
    the DP-16QAM to one of these, or a new recommendation for 400Gbit/s.

    OTN on the optical fiber uses the same modulation as DWDM.
    The difference between OTN and DWDM is visible at the digital
    content (bits and bytes).

    I keep in mind this statement.

    There is not yet indication of 16-QAM for OTN (amplitude modulation
    together with phase modulation).
    There is only amplitude modulation, or only phase modulation.

    I hope it is clear now.

    It begins !

    I expect that the recommendation with DP-16QAM will be published
    after the next plenary meeting of ITU-T SG15,
    So you will have to be patient.

    Kind regards, Huub.



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  • From Michel@21:1/5 to All on Sat Apr 6 13:54:03 2019
    Bonsoir Huub,

    ...I was looking at contributions proposing to add
    the DP-16QAM...

    Many thanks for your information.

    It's fantastic ! With DP-16QAM, a symbol represents 8 bits. So, the 100 Gbit/s transport, in one wavelength, is similar to the rate of 12.5 Gbit/s. The optical fiber length could be almost same as for 10 Gbit/s.

    Kind regards, Michel

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  • From arstpt.michelh@gmail.com@21:1/5 to All on Mon Apr 8 09:38:21 2019
    Just a correction

    The optical fiber length could be almost same as for NRZ 10 Gbit/s.

    Kind regards, Michel

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