Steve Montgomery rounds up the latest developments in fibre technology, discovering that with all other things being equal we’re finally in a position where integrators can choose between fibre or copper simply based on the application, rather than the budget.
Fibre optic transmission of digital signals for data communications, video transmission and computer applications has developed rapidly over the past few years. Early problems with difficulties in on-site termination of cables and the overall cost of equipment and cables have been overcome so that now it is a commonly used and familiar technology.
Stephane Tremblay, engineering director of Magenta Research notes: “There are no longer any financial or practical reasons not to install fibre as the transmission medium of choice in new installations. Terminal equipment is approaching the cost level of standard equipment. Fibre cables can be installed as cheaply as CatX cabling with installers capable of terminating more fibre connectors than RJ45 ones in a given period.”
The choice between fibre and copper will depend upon a number of factors including existing cabling in buildings and the desire to future-proof new installations. Frank Jachetta, managing director of Multidyne, points out another: “A significant factor is secure communication, one that only fibre can offer. It is not possible to secretly eavesdrop on light transmission in the same way that you can with electrical signals.
“This secure solution is why most research facilities, military and strategic government organisations have chosen fibre over copper. Today’s signal bandwidth needs for data and video have also driven infrastructure planners to implement fibre plants over copper solutions.”
Pros and cons for each type of cable mean that the most appropriate one should be selected for each application. Hagai Gefen. CEO of Gefen: “There is no big difference in cost between copper and fibre systems. Copper is a rugged material and very good for most short-range distances. When you must transmit sensitive data or high definition data longer distances, fibre is better. It can handle super long distances and inherently protects against EMI. Copper is ideally suited for short to medium range distances whilst fibre is ideal for long distances and any installations that have to transmit a large amount of high definition data with zero loss of image quality.
“Fibre and copper networks can be mixed. We've seen many installations that use copper cable systems for short range signal transmissions and fibre optics systems taking signals to separate buildings. The nature of the project will determine whether both types can be used and what would work best based on the budget and the distance the signals need to travel.”
Component development and production costs mean that there can be a premium for fibre optic product. This is, however, balanced against installation costs and should be treated on a project-by-project basis.
Derek Miranda, director of marketing for Communications Specialties, Inc. explains: “Integrators and system architects need to take into account the cost of the total system. When dealing with fibre optic products you eliminate the most troubling of installation problems; such as interference, equalisation, deskewing and poor signal fidelity.
“This provides a lower labour cost to install and troubleshoot any given system. Single mode fibre, which has a theoretical infinite bandwidth, now costs less than Cat5 cabling. Lighter weight, smaller form factor and an extremely tight bend radius make working with fibre quite simple. The one thing installers have to learn is that fibre is not fragile: it is stronger than copper; it has a greater tensile strength than steel.
“Integrators and architects need to look at a very broad picture and recognise the impacts that a product selection can have on other parts of the operation even when they seem unrelated. This is the true path to profitability.”
Today, most modern buildings with IP infrastructure are flood-wired with a mix of both copper and fibre. It is common to see a fibre backbone in the vertical risers and copper flood-wired on the floors.
Kevin Morrison, managing director AMX Europe points out the advantages: “Building owners and building developers often flood-wire their buildings to attract new tenants. This is particularly attractive in a multi-tenant, multi-floor building where new occupiers can simply turn on common services like telephony and television, which are passed through the riser, and a flood wired floor allows rapid network configuration.”
Another aspect of installation is the viability and time taken, and hence cost of terminating cables in-situ. On-site installation of fibre is much simpler than it was originally. The majority of connector manufacturers now offer crimp-on style connectors that can be installed in less than five minutes. The key to these quick installation connectors is that the factory has already placed the glass fibre strand in the tip or ferrule of the connector and polished the tip. The field work involves stripping the jacket of the fibre cable, inserting it into the rear of the connector and then crimping it to hold it in place.
It is a huge improvement over using two-part epoxy with a syringe and then polishing the tip in the field; a process that would take more than 20 minutes. Nick Mawer, marketing manager of Kramer Electronics: “We have customers that are able to lift damaged sub-sea fibre cables and repair them in onboard clean rooms whilst at sea in poor conditions. If it can be done there it can be done almost anywhere.”
Miriam Maier Marketing Executive for Neutrik points out new assembly kits for field applications: “Common connectors which can be soldered or crimped onto a cable do not present problems in manufacture. With fibre optic connections it is different. As signals of a fibre optic connection are transmitted via light waves the assembly of the connectors has to be carried out in a clean room with highest precision. However we now supply a kit for field assembly of optical connectors that permits simplified installation and does not require expensive equipment.”
Another advantage of fibre over copper is that less termination is needed. For example; an RGB signal can be transmitted over one single strand of fibre but it would take five coax cables to do the same job, necessitating ten terminations rather than two. Signal multiplexing within fibre networks also allows savings in installation costs as equipment that supports wavelength-division multiplexing (WDM) allows multiple independent transmission signals to co-exist in one strand of glass. A common variant, CWDM, typically allows up to eighteen channels per fibre, thereby further reducing installation and infrastructure costs.
The growth in high speed data communications has seeded the market for fibre–based technology, with quantity and a large number of component suppliers driving pricing down. Coupled with the advantage of massive bandwidth this has, in turn, enabled newer applications such as video transmission systems to take advantage of component availability to develop novel solutions.
Ray Gordon, managing director of Scene Double explains: “Devices that have been used for remote control of computers have traditionally used CatX cabling and been restricted to 100 metres or so, depending upon resolution. This in itself limited their application. Now though, the same type of equipment using fibre interconnection in a high bandwidth system can reach 400 metres with multi-mode cable and 10 km with single-mode. The new generation of high bandwidth optical switches and matrices allows whole systems to be built that offer full video distribution up to 1920 x 1200 resolution.
Frank Jachetta concurs with this view: “Optical routers have now pushed traditional copper routers to the side-line. The ability to connect one optical transmitter handling video, audio or data to a number of receivers in single point or multi-point mode is another step in maintaining overall performance. Anytime you can remove signal processing from a path, you will improve both performance and reliability.”
The core application suite is still conventional data communications as highlighted by Kevin Morrison: “The technological driver is invariably IP traffic and not the distribution of uncompressed AV signals; if AV signal propagation is to be implemented it needs to be encoded in a suitable format.
“Today, AV use of fibre is primarily point-to-point or via a matrix switch on a dedicated fibre network. However, increased performance in compression technology means that high bandwidth digital video over IP networks are close to becoming a reality.”
The IT community has adopted multi-mode fibre as their preferred choice for in-house fibre networks. Originally they used 62.5/125um, but today the preference is on 50/125um because of its bandwidth performance advantage over 62.5um. Multi-mode fibre specifies bandwidth performance as a function of distance.
Typical performance of 62.5/125um would be 250MHz/km, while 50/125um offers bandwidth of between 500-600MHz/km. There is a trade-off between bandwidth and distance; typically this allows a bandwidth of 300MHz for 2 km transmission distance compared with 1200MHz for 0.5km.
The enormous market for data and video communication products is driving manufacturers forward in the design and production of ever-more capable and comprehensive devices, with a plethora of recent new product releases.
We are seeing a strong and valid move toward fibre optic technology in the data and video communication industries, with many new and varied products emerging that are changing the face of data and content distribution. Systems integrators nowadays have greater opportunity and scope to embrace these technologies and deliver comprehensive solutions to customers across all fields of application.