On 26 November 2013 14:50, Giles Barford <[email protected]> wrote: > Generally the grey multimode couplers use Phosphor Bronze Sleeves and > the Blue singlemode use Zirconia Sleeves.
I would say this is very much a generalisation. It is possible that it's an artifact of the quality, or lack of, in the couplers I have seen, but the sleeves I have seen have rarely shown variation of material. > Personally I wouldn't use a multimode coupler on a singlemode fibre. > You will probably get away with it on short runs within the DC. You're talking about the accuracy of alignment between the two ferrules I presume? Whilst this is undoubtedly an issue, if you need to squeeze every dB out of it for your optical budget, I would suggest that either you should be verifying it by testing it or you may be flying too close to the wind? In either case, why would a coupler be used instead of reterminating it correctly? > Multimode is only used for short runs and is generally much more > tolerant of connector loss, the major problem is dispersion which > I doubt would be influenced by using a different coupler. Given the small optical budgets and power levels used on multimode, I've personally found it to be less tolerant of connector loss; a single lossy/dirty connector can knock 50m off your expected range or cause errors and associated pain. Having said that, simply by being multi-mode and having a large core, it is more tolerant of sub-standard or out of spec connectors before causing loss. I believe this is one of the reasons why you might see different materials used for the ferrule alignment sleeves. > I therefore sometimess use blue couplers on Multimode if I can't find > something else. Using a connector built to higher tolerances for something that doesn't need it will usually not result in issues, so I would say this is the "right" way around to do it. -- Maria Blackmore Professional Network Fairy
