I'm having some trouble finding a definite answer. I use a light loss tester to test our fiber (we dont have an otdr) and am unsure as to the acceptable light loss for 1310 SMF. So far I've figured out anything under 1db loss works. Anyone know a better reference?

  • Have you bought a copy of the ANSI/TIA/EIA 568 which details that?
    – Ron Maupin
    Commented Jan 3, 2018 at 20:45
  • 2
    Acceptable loss would be in part determined by the length of the fiber run, how many splices (and type), number of cross connects, etc. Acceptable loss on a 100m direct fiber run with no splices is going to be far different than acceptable loss on a 10km run with multiple splices. Acceptable loss for a network link would be determined by the type and possibly model of the transceivers to be used.
    – YLearn
    Commented Jan 3, 2018 at 21:03
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you could provide and accept your own answer.
    – Ron Maupin
    Commented Apr 1, 2018 at 19:23

2 Answers 2


The exact power budget depends on the PHY used.

Power budgets: 1000BASE-LX10 has a budget of 10 dB (6 dB insertion loss + 4 dB link channel loss - clause 58.5) while 10GBASE-LR has a budget of 9.4 dB (6.2 dB insertion loss + 3.2 dB link channel loss - clause 52.6.3).

This is by IEEE standard of course, mileage on specific transceivers may vary - the higher the budget the longer the reach.

Expected loss: For deployed fiber, OS1 has a maximal attenuation of 1 dB/km (ISO/IEC 11801) and OS2 .4 dB/km (ISO/IEC 24702). Substract .1 dB per (good) splice and .1 to .2 dB per connection.


if you are using a power source and power meter, it is depend on fiber core diameter and type of laser you are using. example for 1310 λ and 9 micron single mode, for each kilometer you have 0.4 db loss and for each connector 1 db and for each fusion 0.5 db.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.