Overview

Fibre-based networks have, over the past few years, evolved in response to the combination of two main developments. The first is the increased consumer demand for greater bandwidth that enables a bundle of multimedia services and applications involving a triple play of voice, video and data services. The second is the declining costs of optical equipment that has resulted in fibre emerging as a proven technology for service providers.

 
Fibre optic networks transmit data, video and voice by converting and translating them into light pulses that are then relayed through the network as an optical signal to the final destination where they are converted back to their original form. In contrast to copper based networks that work by transmitting electric pulses, fibre networks are optical systems that transmit signals using light, typically infrared.  One of its major advantages is that it can carry multiple signals at the same time by using different wavelengths.  It is also less subject to interference and has low signal loss allowing the signal to travel greater distances without further processing.

The two main types of fibre architecture deployed today are either active or passive optical networks (PONs).  Active fibre networks have electronic equipment in the form of repeaters, relays and amplifiers between the customer’s premises and the serving office, whereas, all of this equipment is not required on a PON.  One of the main features of the PON architecture is that it uses passive optical components to guide the optical signal and so it has no power or processing requirements resulting in virtually unlimited service life, thereby lowering overall maintenance costs for the service provider.

Fibre networks are often designed to accommodate other technologies in the overall network configuration to provide end-to-end connectivity with the customer. The primary reason is usually related to cost, as it is often cheaper to use copper or wireless rather than fibre. Fibre to the Node / Curb (FFTN / FTTC) systems transmit the optical signal to a node or a curb in the access network, and an OEC (optical electric converter) converts optical impulses into an electromagnetic signal, before sending it off the last hop over copper. Fibre to the Building / Fibre to the Premises (FTTB / FTTP) is where the fibre is brought as far as the building before the hand-off takes place by copper wire or wireless technologies. Fibre to the Home (FTTH) brings the signal all the way into the premises of the end user.

The main barrier to entry, until fairly recently, in deploying FTTx, the generic term for those technologies, has related to cost. The cost per unit for deploying FTTx has dropped from $ 7,500 per home in the mid 1990s to $1,600 in 2002, to $1,350 in 2004. The estimates today vary between $750 and $1000. [iii]
 

The reasons for FTTx to emerge as the industry standard include a combination of reasons such as its offer of unlimited bandwidth, flexibility to meet triple play demands, reliability, scalability, its status as a future-proof architecture and costs reduction associated with fibre installation. [iv]

Advantages and Limitations

What are the capabilities and advantages of using fibre technologies?

• Fibre is fast emerging as the industry standard for broadband deployment given their huge bandwidth capacity, technical flexibility, low maintenance costs, and as a future-proof solution. It has moved from a niche market to become a standard for global deployment strategy. In Japan and Korea, fibre has become the de-facto standard.
• Fibre has numerous advantages over any other technology.  Fibre has almost an unlimited capability to transmit data with the bandwidth of a single strand of fibre approaching 1 terabit (1,000,000,000,000) per second.  There is exceptionally low loss in transmission, immunity to electronic interference, and it does not emit electromagnetic radiation.  This latter characteristic is particularly important to data security, as signals cannot be picked up and decoded, as is the case with wireless and copper based systems. 

What are the constraints and disadvantages of using fibre technologies?

• Although fibre is the preferred technology for telecommunications network backbone infrastructure because of its superior characteristics, its current deployment in the local loop is limited.  Telecommunications and cable companies have existing connections to their customers and much of the industry has been reluctant to make the necessary investment in FTTH systems.  DSL and cable modems and subsequent advances in the technologies have enabled the industry to deliver many of the current generation of broadband services on the existing infrastructure.  There appears to be a belief that technological advances in DSL and cable modems will provide the necessary bandwidth for future broadband applications.  As evidenced by the experience of operators in Japan and Korea and also Verizon in the U.S., all of whom are rebuilding their systems with fibre to the home, it is not a view that is universally shared.
• Note: A decision to invest in fibre in the local loop is not just a technology decision. There are other legal and regulatory issues, which are actually more important such as rights of use once the fibre has been deployed. This is critical in terms of return on investment and the control of content and services to the end customer.
• The reluctance to deploy fibre in the past had been primarily because of the cost and technical issues related to fibre installation that made it more complicated to deploy. With costs of FTTH declining to on average less than $1000 per installation, it is competitive with existing copper based systems and has the advantage of ensuring that the system will not become obsolete.    FTTH is becoming more common in new residential and business developments and is installed by developers as part of the basic infrastructure.  In the City of Loma Linda, California, it is a building requirement that any new residential unit or extensive renovation to an existing unit must contain wiring capable of providing broadband. [v] 

Fibre Technology and Local Open Access Networks

Fibre is the best technical choice for Local Open Access Networks, but it is not the most viable option in areas that are sparsely populated or where there may not be sufficient demand and ability to pay for the services that can be provided.  The reasons for using FTTH architecture for a LOAN have been well articulated by UTOPIA (Utah Telecommunication Open Infrastructure Agency). [vi]   UTOPIA opted for fibre over other technologies because it was the only one that satisfied all its network criteria of supporting open access for multiple providers, scalable in terms of subscribers and bandwidth, secure, and carrier class providing world-class reliability and protection.  It also has the added advantage that it is the cheapest technology on the basis of cost per Mbps.
 
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