This is an overview of existing PON technologies, their nominal bit rates, and used wavelengths. I will explain some of them in more detail in later posts.
ITU-T
A-PON and B-PON
There are multiple downstream and upstream bit rates specified in G.983.1
| Downstream | 155.52 Mbit/s 622.08 Mbit/s 1244.16 Mbit/s |
| Upstream | 155.52 Mbit/s 622.08 Mbit/s |
Even as B-PON supports dual fiber operation, I will only list the single fiber values.
| 155.52 Mbit/s | 622.08 Mbit/s | 1244.16 Mbit/s | |
| Downstream (nm) | 1480- 1580 | 1480- 1580 | 1480- 1500 |
| Upstream (nm) | 1260- 1360 | 1260- 1360* | n/a |
B-PON operating wavelengths: G.983.1 Table 4 b-f
G-PON
Even if G-PON is typically known for the ~2.5 and ~1.25 Gbit/s datarates, it supports the old upstream bit rates of B-PON. I’m not sure if they were ever (widely) implemented, but as G.984.2 specifies them I will list them here, too.
| Downstream | 1244.16 Mbit/s 2488.32 Mbit/s |
| Upstream | 155.52 Mbit/s 622.08 Mbit/s 1244.16 Mbit/s 2488.32 Mbit/s |
As with B-PON, G-PON supports dual fiber operation, but I will only list the single fiber specifications here.
| 155.52 Mbit/s | 622.08 Mbit/s | 1244.16 Mbit/s | 2488.32 Mbit/s | |
| Downstream (nm) | n/a | n/a | 1480- 1500 | 1480- 1500 |
| Upstream (nm) | 1260- 1360 1290- 13301 1300- 13202 | 1260- 1360* 1290- 13301 1300- 13202 | 1260- 1360 1290- 13301 1300- 13202 | 1260- 1360 1290- 13301 1300- 13202 |
1 reduced band: G.984.5 Table 1
2 narrow band: G.984.5 Table 1
G-PON operating wavelengths: G.984.2 Table 2 b-g
XG-PON (NG-PON1)
This specification does not allow multiple bit rates, so the table is a bit shorter. It uses the max bit rate of G-PON for the upstream direction and uses four times the upstream bit rate in the downstream direction to get near 10Gbit/s.
| Downstream | 9953.28 Mbit/s |
| Upstream | 2488.32 Mbit/s |
Compared to G-PON, XG-PON uses only a 5 nm window in the downstream direction and a 20 nm window in the upstream direction.
| 2488.32 Mbit/s | 9953.28 Mbit/s | |
| Downstream (nm) | n/a | 1575- 1580 |
| Upstream (nm) | 1260- 1280 | n/a |
40G-PON (NG-PON2)
This is an extended version of XG-PON using multiple wavelengths. The bit rates are used in three different rate options: Basic (~10/2.5G), Option 1 (~10/10G), and Option 2 (~2.5/2.5G).
| Downstream | 2488.32 Mbit/s 9953.28 Mbit/s |
| Upstream | 2488.32 Mbit/s 9953.28 Mbit/s |
The OLT can use fixed optics with 100GHz channel spacing, but the ONU needs tunable optics to select the right wavelength in the down- and upstream direction. It is only required to support the first four downstream wavelengths, but there is an extension for up to eight wavelengths.
| Channel | Wavelength (nm) |
| 1 | 1596.34 |
| 2 | 1597.19 |
| 3 | 1598.04 |
| 4 | 1598.89 |
| 5 | 1599.75 |
| 6 | 1600.60 |
| 7 | 1601.46 |
| 8 | 1602.31 |
The frequency in THz is normative, but the wavelength in nm is easier to compare with the other standards.
There are multiple band options in the upstream direction with 50- 200GHz channel spacing (min/max value).
| 2488.32 Mbit/s | 9953.28 Mbit/s | |
| Downstream (nm) | 1596- 1603 | 1596- 1603 |
| Upstream (nm) | 1524- 1544 (wide), 1528- 1540 (reduced) 1532- 1540 (narrow) | 1524- 1544 (wide), 1528- 1540 (reduced) 1532- 1540 (narrow) |
XGS-PON
As the S implies it is a symmetrical version of XG-PON, even if it is technically a subset of the NG-PON2 architecture. It is backward compatible with XG-PON ONU but does not require any support of the 2488.32 Mbit/s bit rate from an XGS-PON ONU.
| Downstream | 9953.28 Mbit/s |
| Upstream | 2488.32 Mbit/s* 9953.28 Mbit/s |
There are two wavelength sets specified, basic wavelength set and optional wavelength set.
| Basic | 9.95328 Mbit/s |
| Downstream (nm) | 1575- 1580 |
| Upstream (nm) | 1260- 1280 |
| Optional | 9.95328 Mbit/s |
| Downstream (nm) | 1480- 1500 |
| Upstream (nm) | 1300- 1320 |
The two-wavelength sets allow the operation of XGS-PON with G-PON, or alternatively XG-PON and XGS-PON on the same fiber.
25G-PON/25GS-PON
This is a standard developed by the 25GS-PON MSA Group and not an official ITU-T Standard. There is an asymmetric and symmetric bandwidth, hence the 25G and 25GS. I will not divide them explicitly into different chapters. It allows for a co-existence of both upstream bit rates.
| Downstream | 24.8832 Gbit/s |
| Upstream | 9.95328 Gbit/s 24.8832 Gbit/s |
As the 25G-PON references the IEEE specification for the wavelengths and not ITU-T, I’m using their specification.
| 9.95328 Gbit/s | 24.8832 Gbit/s | |
| Downstream (nm) | n/a | 1358±2 |
| Upstream (nm) | 1270±10 1286±2* 1300±10 | 1270±10 1286±2* 1300±10 |
25G(S)-PON operating wavelengths: IEEE802.3ca-2020 Table 141-2 and 25GS-PON Specification v2.0 B1 Exception 3
50G-PON
Is currently the newest ITU-T PON Version.
| Downstream | 49.7664 Gbit/s |
| Upstream | 12.4416 Gbit/s 24.8832 Gbit/s 49.7664 Gbit/s* |
The wavelengths are the following with wide and narrowband options for the ~25G upstream direction.
| 12.4416 Gbit/s | 24.8832 Gbit/s | 49.7664 Gbit/s | |
| Downstream (nm) | n/a | n/a | 1340- 1344 |
| Upstream (nm) | 1260- 1280 (Option 1) 1290- 1310 (Option 2) | 1260- 1280 (Option 1) 1290- 1310 (Option 2 wide) 1298- 1302 (Option 2 narrow) | not yet defined |
IEEE
EPON
Is the 1G PON from the 802.3ah group and does only support a symmetrical bandwidth.
| Downstream | 1.25Gbit/s |
| Upstream | 1.25Gbit/s |
| 1.25Gbit/s | |
| Downstream (nm) | 1480- 1500 |
| Upstream (nm) | 1260- 1360 |
10G-EPON
| Downstream | 10.3125 Gbit/s |
| Upstream | 1.25Gbit/s 10.3125 Gbit/s |
| 1.25Gbit/s | 10.3125 Gbit/s | |
| Downstream (nm) | n/a | 1575- 1580 |
| Upstream (nm) | 1260- 1280 | 1260- 1280 |
25G-EPON/50G-EPON
It uses a 25G signal and for 50G two 25G wavelengths are used instead of a higher signaling bitrate.
| Downstream | 25.78125 Gbit/s |
| Upstream | 10.3125 Gbit/s |
| 10.3125 Gbit/s | 25.78125 Gbit/s | 50G* | |
| Downstream (nm) | n/a | 1358±2 | 1358±2 1342±2 |
| Upstream (nm) | 1270±101 1300±101 | 1270±101 1300±101 | 1270±10 1300±10 |
25G-EPON/50G-EPON operating wavelengths: IEEE 802.3ca-2020 Table 141-1 – Table 141-5
