An optical fibre is a thin glass strand that carries light along its length. Light from lasers is shone down the fibre, and is detected by a receiver at the other end of the fibre. Due to their special design, the light within the fibre does not escape out of the sides of fibre (called total internal reflection) and the loss of the light is very low over the fibre length. Because they don’t conduct electricity and lightning, optical fibre cables can be a lot safer than electrical cables because there’s never a risk of receiving a shock. They are also immune from electrical interference caused by heavy industry or other appliances in the home.
Just as broadband consumers in other parts of the world have found, we don’t expect the copper network to meet the future demands for bandwidth that NZ households and businesses will require. Optical fibre is a logical choice for ‘future-proofing’ the network as the need for higher speeds and usage continue to grow over time. Optical fibre is capable of transmitting information at a practically unlimited rate over long distances of tens of km’s. The kind of optical fibre services to be deployed will assure speeds of 100 Mbps and higher, that’s 100 million bits per second – and order of magnitude greater than the broadband speeds most New Zealander’s currently receive on their old copper cables.
The preferred solution world-wide for fibre networks to households is to deploy a ‘shared’ fibre service known as a Passive Optical Network (PON). The electrical equipment to ‘drive’ the optical fibre, including lasers, consumes power. This equipment is located in a central location, a Fibre Access Node (or FAN), and within the Optical Network Terminal unit at each home. A PON uses small dedicated optical fibre runs from the home to a small cabinet in the street, known as a Fibre Distribution Hub (FDH). In this cabinet the individual fibres from a small number of homes (normally less than 32 homes) are combined together into a single fibre back to the central equipment. The PON therefore uses fewer lasers at the central equipment, and also significantly fewer fibres. As a result, the PON uses less power than dedicated fibre
Current PON technologies, such as Gigabit PON (GPON) support speeds of up to 100Mbps per household, or higher if fewer homes are connected to the PON. This speed is achievable at distances of up to 15km from the central exchange. These longer distances mean that fewer ‘exchanges’ will be needed compared to traditional copper-based telecommunication services. Optical fibre is also suitable for large business, schools, universities and research organisations, hospitals and for corporate users. Fibre is already used extensively for some of these purposes today and will be put to even greater use in the future. For institutions that have the highest information requirements, dedicated ‘point-to-point’ fibre services will continue to be available and deployed.
Unlike copper-based telecommunications, optical fibre does not have the ability to carry a voltage or power down the line. In addition, optical fibre services support a wide range of applications – telephony, Internet, TV – which all have different connector types. In order to deliver these connectors and to provide power to the devices connected (eg. ringing the telephone) the optical fibre requires a special network termination unit to be attached. This device is called an Optical Network Termination (ONT), and it requires power to be supplied to it – much in the same way a DSL modem requires power today.
all you want to do is surf web pages, download a few songs, send and receive some photographs, or watch streaming video at current picture quality levels, then the bandwidth provided by today’s cable modems and DSL services is probably good enough for you. But the world is moving toward vastly higher bandwidth applications. Companies like Netflix, Amazon and Wal Mart are offering feature-length movies for download. More people are looking to upload their own home movies into emails or web pages. Consumer electronics companies are coming out with devices that connect televisions to the Internet. High-definition video is fast becoming the state-of-the-art, and one high definition movie takes up as much bandwidth as 35,000 web pages. In the meantime, a growing number of companies are offering “software as service” – meaning you subscribe to applications on the net rather than install them on your own computer. These “cloud computing” applications are now available for word processing, emailing, automated remote file backup, and a host of business and personal services. All of these applications – and many others we haven’t even dreamed of yet – are going to require much greater bandwidth than what is generally available today, even from “broadband” providers. All this adds up to consumer bandwidth demands that are growing at an enormously high rate, and are projected to grow for years to come. Can our current last-mile bandwidth capabilities handle this? Consider the following....