Next Generation Fiber Access Takes Shape

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Commercial deployments of 10G PON officially known as XGPON, are not yet here, but already significant progress is being made on the standard to follow XGPON. On July 16, the Full Service Access Network (FSAN) working group of the ITU announced its recommendation for the NG-PON2 standard, sometimes referred to as WDM PON.

FSAN announced that it had agreed to support a time and wavelength multiplexed technology (TWDM), with optional WDM overlay. Over the past couple years at least eight different technologies had been proposed by various vendors. In arriving at this agreement, the details of the standard are now expected to be ratified in 2013. Typically commercial grade product takes two years to become available following adoption of a standard.

The proposed NG-PON2 standard will be complementary to XGPON and allow for multiple 10G PONs in different wavelength windows-supporting 40+Gb/s. This complementary approach means that service providers can deploy XGPON and be assured NG-PON2 will coexist when it becomes available. This was a change from earlier positions that coexistence was not required. The net effect is that it will encourage a more aggressive approach to XGPON among some operators, while others may just wait until NG-PON2 technology is available. 

There remain a few outstanding questions that will be resolved prior to ratification. Two key questions are will support of RF video be required or an option?  A second key question is what wavelength windows will be used for the NG-PON2 standard?  

Among the eight technologies that were under consideration Calix supported only TWDM, so the FSAN decision is viewed positively by Calix. Calix is architecting its platforms to support 10G PON and multiples of 10G PON, thereby ensuring a smooth migration path from today’s 2.5 GPON to next generation standards, XGPON and NG-PON2.

For a closer look at 10G PON migration strategies see the Calix written article on the July/August cover story of Lightwave Magazine.