Entering a vast, uncharted cave system, the team suddenly lose contact with their advance reconnaissance. A broken fibre-optic link has them fearing the worst, but our man is safe and the link is quickly repaired – then the real trouble begins.

If the monsters we later encounter as the team explore the secret depths of Bruce Hunt’s The Cave are somewhat far-fetched, terminating fibre with crimps and electrical tape is simply ridiculous…

The idea of connection systems using light rather than electricity were a little exotic when The Cave was released, but their growing use in both consumer and professional audio and video – as well as in telecommunications – has made us considerable more aware of their value as an alternative to copper cable. There are also economies in manufacture, as the greater capacity of fibre makes better use of the time taken to assemble a cable.

But these advantages come at the cost of certain wiring considerations that we have long taken for granted – field repairs, for example.

In praise of fibre, we can look to its ability to carry multiple audio and video channels over greater distances and in a far smaller and lighter form than copper cable. This also makes it far easier to deploy than a copper system – in the words of VDC Trading Technical Manager, Nick Chmara, ‘it’s very much lighter and more workable than copper’.

Against this, terminating an optical-fibre cable is almost a surgical procedure… certainly not a job for a soldering iron on the kitchen table. In fact, designing a connector that is able to withstand the rigours of professional use in live sound touring and broadcast drew heavily on Neutrik’s considerable expertise in the design and manufacture of connectors and systems. The result was opticalCon, a real-world connector capable of serving audio, video, lighting and data.

Released in 2005 (same year as The Cave) the connector is not available to the general public, nor even to professional users unless they are registered with Neutrik as qualified to use it correctly. VDC Trading has recently become one of those companies – one of only four in the UK, in fact, and the only one in central London. The pairing of Neutrik’s 35 years of manufacturing interconnection systems and VDC’s 25 years in providing them seems more than coincidental. Fast-and-Wide paid a visit to VDC to get the whole picture...

‘We’re now qualified to handle assembly of optical-fibre cables – and, by Neutrik’s own admission, we address the widest range of industries,’ Chmara says, with obvious satisfaction.

He is sitting with VDC Commercial Director Chris D’Aguiar and Production Manager Paul Marchesi in the newly commissioned optical-fibre assembly room at the company’s London HQ, where Neutrik staff had earlier spent two days satisfying themselves that certification was warranted. 

It’s not quite surgically clean, but it is a step up from the haze of flux smoke that accompanies soldering copper. ‘Obviously things have to be pretty clean in here but it’s not as exacting as it was when fibre first started,’ he says. ‘I think the guys were a little disappointed when they found out that they didn’t have to dress up to work in here.

‘The relationship with Neutrik took some time to iron out but we’re going to run hand-in-hand with them,’ he adds. It’s a good marriage – Neutrik has got a great design and we are able to bring everything we’ve learned from our Tour Grade systems.’

The missing link

Fibre-optic systems work in one of two ways – multi-mode fibre has a larger core-size that makes connection easier but its operational length is limited by modal dispersion, while single mode uses a smaller core. ‘Single-mode multi is very popular in broadcast because you can get such long distances out of it,’ Chmara points out.

Conventional data-communication fibre-optic connectors are designed for permanent, one-time connection rather than mobile applications or the multiple mating cycles. Connectors developed for military applications, were investigated by Neutrik but were not cost effective and have been deficient in various technical areas. Enter Neutrik, with opticalCon…

‘There are eight to ten opticalCon assemblies – duo and quad, and SMPTE versions for ENG,’ Chmara says. ‘You can’t buy the components unless you are a registered Neutrik dealer. Only four people in the UK can buy the components, and we can’t sell them on to other people.

‘We’ve developed our own Van Damme TourLight line that is basically a tactical touring four-core quad that comes as both single-mode and multi-mode. At the moment, as part of the opticalCon remit, we will be offering both duo assemblies and quad assemblies. We’ve developed this because there is quite an even split with us – single mode being popular with the broadcast industry and potentially video event transmission companies, and the multi-mode being used by the touring industry for audio applications.’

Assembly of a fibre-optic cable requires the cable to be prepared and LC connectors attached, including the use of a small amount of epoxy that must be cured in an oven. The cable fibre must then be cleaved and cleaned with a ceramic tile – a particularly critical stage of the procedure, as the fibre is thinner than a hair and easy to crack. It must then be hand and air polished using progressively finer abrasive pads. Then it is inspected with an optical scope to ensure the fibre end is not scratched or cracked, and is free of dust and residue from the polishing process. Each individual connector is tested for insertion loss and return loss (dependent on the cable length). Once passed, each connector is issued a certificate that accompanies its delivery.

‘You can see how delicate the assembly is,’ Chmara says. ‘If it’s going to survive in a touring environment, we have to get it right at this stage, but once the connectors are crimped and closed, that’s what makes it tour safe. The connectors are designed to be rugged enough to protect the delicate elements. Misuse is the key element in most of the damage we have seen.’

The Van Damme TourLight line uses a PUR inner sheath, which is a tour grade component, and a special PVC composite outer from VDC’s copper-based technology. The practical considerations of taking it out on the road in a flightcase are very similar to copper 

‘By the end of the year, people will have a lot more confidence in it,’ Chmara says. ‘The adoption process began with the bigger hire companies, and now it’s spreading into the presentation companies and other sectors as people become more confident and comfortable with it. Come May-June – when the festival season begins, and we cover the tours and festivals with PA companies, lighting companies and the bands themselves – we will have to go into mass production.

He identifies education as the next stage in promoting this confidence: ‘It’s as simple as opening a connector to show what’s going on,’ he says. ‘When people understand that, they know how to take care of it and use it.’

And the signs that he is right are already there. Successive improvements that Neutrik has made to the opticalCon connector are accompanied by consistent uptake of fibre-optic systems by both manufacturers and end-users.

‘When we first started dealing with this in 2010, it was one or two pieces a year, then in 2011 it started a gradual increase, and between 2012 and 2013 it increased by somewhere around 75 per cent,’ Chmara confirms. ‘Now, around one in ten of the bigger jobs we handle are fibre based. Neutrik globally is seeing the same sort of numbers.

‘We anticipate that the significant investment that this has required to set this operation up is going to add considerable revenue to our 2014 budget.’