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Fibre Optics

Discussion in 'Wireless & RF Design' started by DeeBee, Aug 14, 2008.

  1. DeeBee

    Thread Starter New Member

    Aug 14, 2008
    Hi all,

    Just had a few questions about SM fibre losses if anyone had a minute to help a noob out....

    What sort of losses in dB would you expect over certain splices? For example, an ST bulkhead connection, a fusion splice, a hot melt? Does it depend on the modem (1550 > 1330nm)? Does having an inline WDM effect any of this? What sort of loss would you expect per km of line?

    Tried to research this but everything seems to cover theory rather than the ´hands on`information....

    Any help greatly appreciated! :confused:
  2. ftcnet

    New Member

    Jun 7, 2008
    Patch-panel ST connector loss should be in the range of .2db - 1db.

    Mechanical multimode splices are typically ~ .2db.

    Single-mode fusion splices can achieve .05db.

    ref: Corning Single Fiber Fusion Splicing app note.
  3. thingmaker3

    Retired Moderator

    May 16, 2005
    EIA/TIA standards call for not more than 0.3dB loss at any SM splice or connection. I've measured some ST bulkhead connectors as low as 0.05dB, but only rarely.

    Wavelength can indeed make a difference, but I don't recall it ever being more than 0.01 or 0.02.

    A team I was on a decade or so ago also found turning a fiber in a crimp-type ST connector sleeve prior to crimping can improve performance. We used an ordinary red "fiber flashlight" and a bit of black paper to achieve minimum loss. Obviously, we were only able to manipulate one end in this manner. I suppose one could cut the first end off after dialing in the second and then re-terminate with this method. Such effort would be expensive.