24/02/2010

Fibre Capacity Limitations in Access Networks | Ofcom

Fibre Capacity Limitations in Access Networks | Ofcom

Ofcom have commissioned Analysys Mason (of Edinburgh) to write a report about fibre technologies and how they relate to fibre-to-the-home (FTTH) and fibre-to-the-cabinet FTTC) deployments.

The report goes into the differing fibre technologies such as single vs multi-mode fibre, optical transceiver types (such as differing lasers), repeaters/amplifiers and differing transmission types (GPON, PTP and WDM PON).

There's a nice analogy of comparing a road system to a fibre, you have to consider the length of the road, the wide of the road and the lanes and the speed limit and the effect they have on the available capacity i.e.

* Increase the width of the road. Relates to the available spectrum which means more spectrum, more capacity. However the technology may not be available (at the optical or fibre level) to support extra spectrum.

* Increasing the speed limit. This relates to the frequency of the light being sent down the fibre, which can be limited by both the fibre characteristics and the optical transceivers.

* Increasing the number or lanes (or decreasing the size of the lane). More traffic can pass down the increased lanes, however at some point there is interference between lanes and traffic on neighbouring lanes will collide.

The report goes into considerably more technical detail, but an interesting read if you're into fibre technologies and what happening in that area.
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