Using MM Fiber cable for Loopback test on SM port?

[CiscoBrownBelt]

Just to test to see if a port is operational, using a short let's say 3M MM fiber as a loopback cable however on a SM port on an ethernet port on a router or even media converter is sufficient correct or no?

[balaji.bandi]

you need single lead just loop the fibre light.

Best way to test it, if you have 2 SFP port (make them layer 3 connect to test if that working)

[CiscoBrownBelt]

Yes but what if  you don't. Will using what I described be sufficient given it is a single mode port but a single mode fiber just split to be loopbacked?