Home Forums SYSTEM Difference between TWDM and DWDM

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    • #16902
      Heitor Galvao
      Participant

      A brief explanation please

    • #16903
      Heitor Galvao
      Participant

      Due to increasing amount of applications that require high bandwidth and high speed, standardization currently being conducted for future PON, named next generation Optical access network State 2 (Next Generation Passive Optical Network 2, NG-PON2). The main requirements for NG-PON2 are: support aggregate rate all the ONUs of 40 Gb/s of internet support of mobile devices (mobile backhaul), offer service of 1 Gb/s or more to users, 40 miles of range, 64 units of ONUs and 40 miles of range differential The Group of full service access network (The Full Service Access Network FSAN Group) considered many architectures of networks to meet the requirements of NG-PON2. Among them, were studied: the Division Multiplexing PON wavelength (Wavelength Division Multiplexing PON, WDM-PON), the Orthogonal Frequency Division Multiplexing PON (Orthogonal Frequency Division Multiplexing PON, OFDM-PON), and multiplexing by wavelength-division and Time PON (Time and Wavelength Division Multiplexed PON, TWDM-PON).
      I understand now what’s more TWDM now is as follows for example in this article attached it uses DWDM and CWDM in the downstream and upstream respectively, what would be the difference in the case?

    • #16940
      Ravil
      Participant

      Hi Heitor,
      Briefly speaking the main difference between TDWM and DWDM is the multiplexing domain: time and wavelength for TWDM system on one side and just a wavelength (with dense spacing) for DWDM. Let me know if you have more question.

    • #16941
      Ravil
      Participant

      Time division multiplexing (TDM) is based on Rec. G.707, G.7o3 of ITU-T.
      Wavelength division multiplexing (WDM) is based on Rec. G.694 of ITU-T.

    • #16942
      Heitor Galvao
      Participant

      now is as follows for example in this article attached it uses DWDM and CWDM in the downstream and upstream respectively, what would be the difference in the case?

    • #16953
      Ravil
      Participant

      You mean, the difference b/w DWDM and CWDM?

      • #16955
        Heitor Galvao
        Participant

        This

        Attachments:
        • #16982
          Damian Marek
          Participant

          The difference is the channel spacing of the wavelenegths. In DWDM usually it is around 0.8 nm whereas for the CWDM it can be larger for example 20 nm.

          +2
        • #16991
          Heitor Galvao
          Participant

          Thanks Damian

    • #17002
      Ravil
      Participant

      I agree with Damian’s explanation. Just want to add from myself that according to your scheme, you have high bit-rate for download traffic corresponds to DWDM system which provides high capacity. On the other hand the bit-rate is lower for upstream (which is usually the case) and CWDM system is used which satisfies this requirement.

      • #17006
        Heitor Galvao
        Participant

        Thank you, you’re welcome Ravil

    • #17004
      Heitor Galvao
      Participant

      From what I understand DWDM is characterized by using separation between channels rather small, usually of 0.8nm, and to place all its channels of optical amplifier operation (EDFA), iso is, between 1560nm and 1620nm. It should be used then to the downstream direction. While the CWDM using separation of 20nm channels and does not restrict the EDFA window, which relaxes the tolerance of the components and reduces system costs more also reduces their transmission capacity. CWDM should be used in the upstream direction.

      +1
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