Since its first proposal in 1966 the economics behind optical fiber technology have changed radically. The major components within the communications system comprise the fiber (and the resulting cable), the connections and the opto-electronic conversion equipment necessary to convert the electrical signal to light and vice versa.
The remainder of this book deals with these topics individually whilst building in a modular fashion to ensure that fiber optic cabling networks most fully meet their potential as operating systems.
In the early years of optical transmission the relatively high cost of the above items had to be balanced by the savings achieved within the remainder of the system. In the case of telecommunications these othervsavings were generated by the removal of repeater/regenerator stations.
Thus the concept of ‘break-even’ distance grew rapidly and was broadly defined as the distance at which the total cost of a copper system would be equivalent to that of the optical fiber alternative. For systems in excess of that length the optical option would offer overall cost savings whereas shorter-haul systems would favour copper – unless other technical factors overrode that choice.
It is not surprising therefore that long-range telecommunications was the first user group to seriously consider the optical medium. Similarly the technology was an obvious candidate in the area of long-range video transmission (motorway surveillance, cable and satellite TV distribution). The cost advantages were immediately apparent and practical applications were soon forthcoming.
Based upon the volume production of cable and connectors for the telecommunications market the inevitable cost reductions tended to reduce the ‘break-even’ distance. When the argument is purely on cost grounds it is a relatively straightforward decision.
Unfortunately even when the cost of cabling is fairly matched between copper and fiber optics the additional cost of optoelectronic converters cannot be ignored. Until certain key criteria are met the complete domination of data communications by optical fiber cannot be achieved or even expected.
These criteria are as follows:
• standardization of fiber type such that telecommunications product can be used in all application areas;
• reductions in the cost of opto-electronic converters based upon large volume usage;
• a widespread requirement for the data transmission at speeds which increase the cost of the copper medium or, in the extreme, preclude the use of copper totally.
These three milestones are rapidly being approached; the first two by the application of fiber to the telecommunications subscriber loop (to the home) whilst the third is more frequently encountered due to vastly increased needs for services.
Meanwhile the economics of fiber optic cabling dictate that while ‘break-even’ distances have decreased the widespread use of ‘fiber-to-thedesk’ is still some time away. There is a popular misconception in the press that the ‘fiber optic revolution’ has not yet occurred. It is evidently assumed that the revolution is an overnight occurrence that miraculously converts every copper cabling installation to optical fiber. This is rather unfortunate propaganda and, to a great extent, both untrue and unrealistic.
In telecommunications, optical fiber carries information not only in the trunk network but also to the local exchanges. For motorway surveillance the use of optical fiber is mandatory in many areas. At the data communications level all the major computer suppliers have some fiber optic product offering within their cabling systems. Increasingly process control systems suppliers are able to offer optical solutions within large projects.
But in most, if not all, cases the fiber optic medium is not a total solution but rather a partial, more targeted, solution within an overall cabling philosophy. There is no ‘fiber optic revolution’ as such. There is instead a carefully assessed strategy offering the user the services required over the media best suited to the environment.
What cannot be ignored is the fact that fiber optic cabling is specifically viewed as a future-proofed element in the larger cabling market and as such operates more readily as an operating system deserving deep consideration at the design, installation, documentation and post installation stages.
As has been seen, the immediate cost benefits of adopting a total fiber optic cabling strategy are dependent upon the transmission distance. With the exception of telecommunications and long-haul surveillance systems the typical dimensions of communications networks are quite limited.
The local area network is frequently defined as having a 2 kilometre span. The vast majority of fiber optic cabling within the data communications market will have links that do not exceed 500 metres. Such networks, when installed using professional grades of optical fiber, offer enormous potential for upgrades in transmission equipment and services.
The choice of components, network topologies, cabling design, installation techniques and documentation are all critical to the establishment of a cabling network which maximizes the operational return on investment.