Innovation UK > News > Innovation UK Vol5-1 > Investment in new access network technologies

The Photonics KTN has been exploring opportunities for next-generation access in the UK, with workshops with key stakeholders held in March and September 2008, and inputs provided to OFCOM consultations. One important output is a concern that the UK will be left behind other countries in Europe and the rest of the world in the race for super-fast broadband, and that this will harm the UK?s creative industry sector which relies on high-speed internet access to carry out business. The recently announced initiative by BT to roll out fibre to the cabinet (FTTC) is to be welcomed, as is the raising of public awareness of fibre through Virgin Media marketing of their hybrid fibre coaxial network, but the concern is that both these hybrid fibre/copper solutions are not as future-proof as fibre all the way to the home (FTTH) and will be eclipsed by what is already happening in other countries.

Participants at the recent FTTH Council meeting in Copenhagen were upbeat about developments in FTTH around the world despite the global financial gloom. Europe still lags way behind Japan, Korea and the US on fibre deployment but some countries in Europe are moving forward, especially Scandinavia and Holland. Growth in Europe is generally not being driven by the incumbent operator. It is widely accepted that getting fibre close to the home ? ideally into the home ? is the only way to deliver the new video-intensive interactive services emerging and driven by recent phenomena such as YouTube. Interactive video is already appearing in HD and in Japan Super HD is being developed. Only the extensive use of fibre in the distribution network will allow these services to be delivered symmetrically.

For FTTH there are now several flavours of the technology, which are fighting for their positions and are largely driven by the need to standardise to reduce costs. However, the rate of technology change means that new and better solutions become available even before the ink is dry on an existing standard.

GREEN FIELD BUILD

For green field build where cable duct and fibre is being put in for the first time there is an attraction for pointto- point fibre, one fibre from the central office to every home. This is a scheme that has been favoured in Scandinavia and Holland and has the ability to offer futureproof services by just changing the terminal equipment as new services become available. It is less attractive for the incumbent operator who already has an investment in ducts, which may already be full of copper.

For the incumbent, the solution is either fibre to the cabinet, with existing copper connection the last 100m or so (which limits reliable speeds to around 20Mbit/s), or passive optical networks (PON). With a PON, the fibre from the central office to the street cabinet is connected to an optical splitter network which shares the primary fibre feed to many houses. This scheme reduces the fibre required and relaxes the use of duct space compared to point-to-point. To time-share the fibre in a PON there have been a number of protocols developed over recent years such as BPON, GEPON and GPON.

NEW TECHNOLOGY

The new technology on the block for FTTH is WDMPON, wavelength division multiplexing passive optical network. This combines the advantages of future-proof point-to-point with the fibre and cable reduction of a PON. In this scheme each customer has access to a separate wavelength of light on the fibre. A single fibre can carry more than 30 wavelengths in early WDM-PON systems and possibly 1000s in future systems. Although such a network is seen as the holy grail there are a number of challenges to make these schemes economically attractive, in particular the development of low-cost technologies for handling many wavelengths. Having a separate laser with a different wavelength for each customer would be a major inventory problem for the network operator.

The solution is to make the customers? equipment ?colourless? when first installed and be programmed by the network itself. This is an approach which CIP (www.ciphotonics.com) in the UK have been particularly active in and have developed world-leading technology which is now being evaluated by major telecommunication equipment manufacturers.

The Photonics KTN is working to cement the political vision to invest in a FTTH network in the UK using these new and future-proof technologies, with the competitive benefits this will bring to UK industries and the nation as a whole.

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