I lease some SMF strands about 15km long, over which I'm using CWDM (1490-1610nm GBICs). I am shooting different colors in different directions over a single strand, so electronics at each end of the strand are transmitting at some wavelengths, and receiving at others.
On one strand, all GBICs at one end of the fiber show CRC errors on the data being received; the GBICs at the other end of this strand show no CRC errors. I tried testing using a second strand, with ZX GBICs (1550nm, 2 strands, no CWDM mux), and I find that the same end consistently receives CRC errors over the suspect fiber strand. But if that end transmits over the suspect strand, the other end has no CRC errors. It seems as though the suspect strand only causes trouble for light transmitted in one direction.
Unfortunately, I don't have any real FO test equipment beyond a power meter. My fiber provider shot both ends with an OTDR and said "looks good to us"; any hints on what I should ask for to get them to see what I'm seeing?
Thanks, Phil