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Ask John Bruno

John shares his knowledge of fiber optics by answering your specific questions


What are the advantages and disadvantages for using splice-on and mechanical connectors? Which of these connectors is more feasible for terminating drop cables?

Bruno's Answer

Before I answer this question I need to make a statement. As I list the options for field installing a connector keep in mind when at all possible a factory pre-terminated cable with an attached pulling eye for installation exceeds any and all options for field installation of an optical connector. With that being said I understand the need for field installation (broken, different, etc.) of an optical connector.

There are really only three ways to install a fiber optic connector and all of them have their pros and cons. Connectors can be field installed in one of three ways, the epoxy and polish method, a quick term (mechanical) or fusion splicing a factory made pigtail or Splice On Connector (SOC). I have never hidden the fact that I support fusion splicing as the best method for field installing a connector.

The traditional connector installation using epoxy and a polish method may have the advantage of low initial tooling costs but that is about where the advantages end. This method tends to be labor intense with high connector scrap rates, the use of numerous consumables and requires a higher skill level than other options. The epoxy and polishing method though still utilized is used less and less for field installations.
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The mechanical connector option while quick and efficient does also present its challenges. Initial kit cost for this type of connector can be as high as $1,800.00 and the connectors themselves are much more expensive. The draw to these connectors is the speed at which they can be installed with a lower skill level. When using a mechanical connector you are sacrificing quality, specifically in higher attenuation and ORL (Optical Return Loss). When considering your specific situation (drop cables and Singlemode) the disadvantages of the mechanical connector should rule out its use.
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Fusion splicing in my opinion, as I stated earlier, is the single best way to install an optical connector. Gone are the days of a fusion splicer being unaffordable and difficult to use, with a cladding alignment splicer selling for as low as $3,000 and the utilization of removable chucks, fusion splicing has never been more appealing. Let’s not forget the other advantages of using a factory made, pretested, low attenuation/Low ORL pigtail or Splice On Connector (SOC). Every advantage swings to the use of a fusion splicer to install connectors in the field.
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To address you second question regarding Drop Cables and fiber connectors the choice is an obvious one. Fusion splicing is the ONLY method I would recommend if factory cables are not an option. The nature of drop cables is long distance, high power Singlemode fiber. This scenario requires low Back Reflections (ORL) and attenuation and the only way to get that is by fusion splicing your connectors.