Hello, everyone!
Today, I will continue to write about new PON technology – 25G-PON. This is the last article about this topic.
Modern OLTs can support new generations of PON - XG-PON, XGS-PON, 25G-PON, etc. The 25G-PON standard uses new wavelengths so that it can coexist with GPON, XG-PON or XGS-PON. This is very important because ODN is the largest and most expensive part of the network. In addition, many GPON, XG-PON or XGS-PON users will not immediately use 25G-PON.
25G-PON offers 2.5 times higher data rates downstream and upstream than XGS-PON. One of the problems that occur is dispersion. With a large bit rate, dispersion also occurs. In order to reduce the dispersion, it is done in an O-band. 25G-PON technology supports both symmetrical transmission (25/25) and asymmetrical transmission (25/10). When it comes to ONU devices, this technology does not require expensive 25G/10G ONU devices.
Figure 1. One ODN, three PON standards – GPON, XGS-PON and 25G PON
(https://onestore.nokia.com/asset/205049?_ga=2.241813383.488345712.1636730218-1155300743.1632396758)
The introduction of a new standard in the existing ODN network with the current GPON, XGPON or XGS-PON standards, requires 25G-PON to use different wavelengths. The 25G-PON standard uses 1358 nm for downstream, while for the upstream it can use different wavelengths: 1300 nm, 1270 nm or 1286 nm. It depends on which PON standard is used in the system. So we have three options:
1300 nm when there is XG(S)-PON in the system.
1270 nm when there is a GPON in the system.
1286 nm allows the presence of all standards 25G PON, XG(S)-PON and GPON.
It is very important to continue with the further construction of the ODN segment of the PON system. Because all future generations of PONs can use that optical infrastructure. Further development of PON technologies is underway - 50G-PON and 100G-PON. From 50G-PON far 8 to 10 years, while 100G-PON is still a distant future. 50G-PON and 100G-PON will require new lasers, new amplifiers, and optimization will be required to obtain acceptable costs.
This is the end of this topic. I hope you learned something new.
Thank you!
Reference:
https://www.bbcmag.com/broadband-applications/25g-pon-the-future-of-broadband
https://www.lightwaveonline.com/fttx/pon-systems/article/14180371/ieee-8023ca-25g50gepon-standard-approved
https://onestore.nokia.com/asset/205049?_ga=2.241813383.488345712.1636730218-1155300743.1632396758
