How does fibre optic broadband work?

Superfast broadband is all over the news at the moment, with BT broadband (www.BT.com) rolling out its fibre optic broadband packages and Virgin Media (www.Virginmedia.com) offering speeds of up to 100Mb broadband.

Even the government is getting in on the action, promising the best broadband in Europe by 2015, and pledging £830million towards building a next-generation network.

Superfast broadband

Although all fibre optic broadband packages offer much faster speeds than you would get from traditional internet services, the actual speeds you receive depend on a number of different things.

The actual package you sign-up to will decide both your download and your upload speed.

At present, BT infinity (www.BT.com) offers speeds of up to 40Mb broadband, with up to 10Mb upload speeds, to more than four million homes and businesses across the country. It plans to extend this to cover two-thirds of the UK by 2015, with around a quarter of its full network being able to connect at up to 100Mb broadband

Virgin Media already offers speeds of up to 100Mb, though the package won't be fully rolled-out across its network until mid-2012, says the provider.

However, almost 13 million customers connected to the cable network can already get speeds of up to:

• 50Mb broadband
• 30Mb broadband
• 10Mb broadband

The last mile

Both BT and Virgin Media use fibre-to-the-cabinet (FTTC) technology to deliver the majority of their superfast broadband services.

This means that fibre optic cables, which carry more data at faster speeds, are run from the BT exchange or the Virgin Media hub to the green telephone cabinet on your street.

But from there, the two providers each use a very different type of connection that can make a real difference to the speeds you receive.

Known as the "last mile", the connection between the cabinet on your road and your home could be made up of a number of different wires, some of which give you far better speeds than others.

Virgin Media's very fast, reliable cable connections are possible because of the cables that it uses to connect your home to the cabinet.

These electrical cables, known as coaxial cables, do not lose broadband speed over distance, maintaining your broadband speed through the length of your connection. This allows customers to receive at least 90% of their advertised speed, says Virgin Media.

This means that even customers on the provider's cheapest 10Mb package "typically receive 9.68Mb".

On the other hand, BT uses traditional copper wires for the last mile on its FTTC connections. This means that you might still lose some of your connection speed if your street cabinet is too far from your home.

BT says that it expects customers on its 40Mb package to receive an average of around 30Mb and a "guaranteed minimum" of 15Mb.

Fibre-to-the-home

Fibre-to-the-home (FTTH) technology runs fast fibre optic broadband cables direct to your home, bypassing the streetside cabinet completely. For BT, this means much faster connections than are currently available through its Infinity network.

BT expects to make up around 25% of its fibre network with fibre-to-the-home connections, offering speeds of up to 100Mb from spring 2011.

Virgin Media is trialling FTTH in some areas that are not currently cabled, such as Woolhampton, Berkshire, using electricity poles to bring its superfast broadband to new areas.

However, the provider says that its current network of fibre optic cables coupled with coaxial connections is capable of handling future speeds of up to 400Mb.

Can I get superfast broadband?

Virgin Media's cable network covers around 51% of the UK, though it is in the process of extending its network to another 500,000 homes.

BT says its 40Mb Infinity network will have passed around five million premises by this spring.

So where you live plays a huge part in deciding whether or not you can get fibre optic broadband and which type. To find out, run a postcode search compare broadband providers before choosing a package.