I am confused about SFP transceiver choice, and compatibility with single mode fiber based on the fiber's OS rating.

My only question is, when choosing an SFP is it necessary to consider the OS rating of a single mode fiber? Or is it enough to know the cable length?

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    Aug 11, 2017 at 4:09

2 Answers 2


The OS rating of single mode fiber should have no bearing on your choice of transceivers.

Both OS1 and OS2 will work with the most popular single mode transceivers (most of which use wavelengths around 1310nm and 1550nm). This includes 1000Base-LX/LX10/EX/LH/ZX and it is the transceiver which larger determines the distance the signal will propagate, not the fiber.

The main difference in OS1 and OS2 is the construction of the cable, although OS2 may specify cable with a lower attenuation specification (depending on when and under which standards it was manufactured).


In short, no - it doesn't matter. What matters is your distance requirements (as you stated).

  1. Choose optic based on distance requirements - See here. (Doesn't have to be Cisco obviously, but the optical standards are the same.)

  2. Choose fiber based on optic.

And, other than that, it's really this simple:

  • Using SR optics? Use multimode fiber (50 or 62.5 micron). See here.
  • Using LR/ER optics? Use singlemode fiber (9 micron). See here.

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