WDM PON in 200 words and one diagram

Thought by many to be the next thing in FTTH, WDM PON (Wave Division Multiplexing Passive Optical Network) provides the dedicated bandwidth of a point-to-point network with the fiber sharing inherent in PON networks. Not a standard today, WDM PON is not yet fully defined, but carriers and vendors expect up to 32 subscribers to be served by a single WDM PON access fiber.

The WDM PON architecture is identical to that of EPON and GPON (and their 10G versions) FTTH architectures. However, instead of a splitter, WDM PON has an Arrayed WaveGuide (AWG) filter that separates the wavelengths for individual delivery to subscriber ONTs.

Advantages of the WDM approach are inherent in the completely separate downstream wavelengths for each subscriber. This provides more bandwidth to each subscriber, more security, and better operational control since there is no interference in the downstream direction among the various wavelengths.

The biggest disadvantage of WDM PON is its cost (and its maturity as a FTTH technology). Each subscriber requires its own dedicated transceiver at the OLT, and this is one of the cost advantages of the other PON technologies lost with WDM PON. Additionally, the AWG filter is expected to be more expensive than the splitters used with GPON, EPON, and BPON.

The diagram below shows a typical WDM PON network.

© 2009, The Product Group LLC. All rights reserved.

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1. Fiber says:

   October 6, 2009 at 7:10 am

   South Korea is leading user of WDM PON. WDM PON is considered as the ultimate aim for many service providers at present.
2. photon says:

   January 31, 2010 at 4:58 am

   although WDMPON is a costly network, but it offers no more payment in the future because it can support (each user) up to 2.5Gbps without moving one inch from the infrastructure, whereas in GPON, it is a really night mare if we think to increase the BW.

   the problem for the WDMPON now days is, there are no standard at which the data can be down/up streamed, because there are lot’s of ideas in mind, some researchers used FP-LD at each ONT, others used RSOA, some of them used both one FP-LD at the OLT and RSOA at each ONT to reduce the cost.
   but i believe that this NW will be the NGPON.