Testing of randomly selected fibre optic assemblies, conducted by Siemon Labs, has
highlighted the performance risks associated with low-cost generic products.

Siemon, a global manufacturer of IT network cabling and infrastructure systems, has released the results of comprehensive benchmark testing on optical fibre assemblies.

Performed by Siemon Labs, these tests included randomly selected fibre jumpers from five well-known global brands, including Siemon, as well as jumpers from four low-cost generic assembly houses. The results clearly showed a significant performance gap between the global brands and the generic products, with a significant number of generic assemblies failing to meet minimum standards requirements across a range of performance-critical parameters.

In terms of optical performance, Siemon Labs tested all assemblies for insertion loss (IL) and return loss (RL). While all assemblies passed minimum IL requirements, three out of four generic suppliers had RL failures.

In addition to optical performance, the tests also covered standardsbased requirements for fibre end face geometry, specifically fibre end face radius of curvature, apex offset and fibre height. These three critical mechanical characteristics of the fibre end face control the alignment and actual physical contact between fibre cores to ensure reliable signal transmission. While only one global supplier assembly experienced an end face failure, none of the generic assemblies passed all three minimum requirements. The generic brands fared even worse against Siemon’s more rigorous internal performance requirements.

Standards-based visual inspections were also performed, and the results highlight the potential performance impact of contamination and fibre core defects. Fibre core fractures and contamination on ferrules, alignment sleeves or dust caps degrade IL and RL performance, making test results completely unpredictable and causing unnecessary problems such as wasted time in trouble-shooting test failures and false passes that cause non-compliant channel performance on ‘day two’. All samples, except those from Siemon, exhibited some form of contamination and failed visual inspection. After proper cleaning, 75% passed with some defects and 25% failed even after cleaning.

While lab tests on optical parameters and connection attributes provide a very strong indicator of an assembly’s overall quality and performance, it does not guarantee that the assembly will survive in the real world. As such, Siemon Labs performed mechanical reliability testing against standards requirements for cable pull, flex, torsion and retention, parameters designed to ensure that assemblies can endure the mechanical stresses of installation and maintenance in a real-world network and still deliver reliable, long-term performance. These tests once again showed a large quality gap, with all global brands indicating 100% passing results while not a single low-cost supplier made it through without significant failures.

The full results of the Siemon Labs testing highlight the significant risks in specifying low-cost generic fibre jumpers over well-known, quality global brands as well the dangers in considering a passing IL field test as an indication of overall assembly performance. Substandard RL, non-compliant end-face geometry and poor mechanical reliability dramatically increase the likelihood that generic assemblies will degrade overall network performance.

“Users make significant investments in fibre network equipment for its ability to deliver high-bandwidth performance. And that performance is choked by cheap, substandard jumpers,” Robert says.

“For example, a 24-port, 10GbE fibre switch costs about $10,000. If an OM3 LC fibre jumper costs about $20 from a generic supplier and $25 from a highquality global brand, you’d save a total of about $120 if you used generic jumpers with that switch. Is $120 in jumper savings worth jeopardising the performance of a $10,000 piece of equipment? If you factor in potential downtime, troubleshooting and replacement jumper costs, using anything less than the highest quality jumpers makes no sense.”

The full results of Siemon Lab’s fibre assembly testing are included in a whitepaper titled: A Closer Look at Fibre Optic Cable Assemblies, available online at www.siemon.com/go/fibrejumper.