PON کے طول موج پلانز اور بقائے باہمی

ہماری ٹیم ترجمے پر کام کر رہی ہے۔ یہ مضمون عارضی طور پر اردو میں دستیاب نہیں ہے، اس لیے اسے انگریزی میں دکھایا جا رہا ہے۔

Every PON generation is defined as much by its wavelengths as by its bit rate: the downstream and upstream colours are chosen so that a new generation can share the same fibre and splitters as the old one. Knowing the plan tells you what a PON module is and whether it belongs on a given network.

Wavelength plans

System	Downstream	Upstream	Notes
GPON	1490 nm	1310 nm	ITU-T G.984
EPON	1490 nm	1310 nm	IEEE 802.3ah; same colours as GPON
RF video overlay	1550 nm	—	analogue TV carried alongside GPON
XG-PON / XGS-PON	1577 nm	1270 nm	ITU-T G.987 / G.9807.1
10G-EPON	1577 nm	1270 nm	IEEE 802.3av; matches XG(S)-PON colours
NG-PON2 (TWDM)	1596–1603 nm	1524–1544 nm	four tunable channel pairs, ITU-T G.989

The upstream band sits in the O-band (1260–1360 nm), where uncooled, inexpensive ONU lasers work well; downstream uses the longer wavelengths where fibre loss is lower.

Coexistence

Because GPON (1490/1310) and XGS-PON (1577/1270) use different colours, both can run on one fibre plant at the same time. A passive coexistence element (a WDM filter, often called WDM1r) at the central office combines the two OLT ports onto the feeder fibre; at the customer, each ONU's filter passes only its own pair. This is how operators upgrade subscribers one at a time without touching the outside plant.

NG-PON2 goes further: ONUs carry tunable optics and are assigned one of several wavelength pairs, so capacity can be added by lighting another pair.

Reading a PON module

The wavelength fields in module memory identify the system:

Tx 1490 / Rx 1310 → GPON/EPON OLT side; Tx 1310 / Rx 1490 → ONU side.
Tx 1577 / Rx 1270 → XGS-PON OLT; Tx 1270 / Rx 1577 → XGS-PON ONU.

A module with the wrong pair for the network will simply never see light from the other end. See PON transceivers: OLT & ONU.

In CodingBox

CodingBox shows the transmit wavelength and identity of a PON module on the Check transceiver screen, so an OLT SFP and an ONU stick — or a GPON and an XGS-PON module — can be told apart before they are installed.

اگر آپ کو اس مضمون میں کوئی غیر درست بات یا غلطی نظر آئے تو متعلقہ حصہ منتخب کریں اور Ctrl+Enter دبا کر ۔