On Thu, 12 Dec 2013, Keith wrote:
Fixed optics, there are no transponders, just a passive mux. No filters, though there is a pad on our side. Light levels on our side are good and within spec. I have been trying to find out from the SP what theirs are at presently, but when the circuit was first lit levels were taken and found to be within spec on both ends.
Another possibility is that the fiber you're using has higher attenuation at 1471nm than at 1310. While 1471 is outside of the 'water peak' band (E band - 1360-1460nm, centered at 1383nm, iirc), the type of fiber could could still have higher attenuation that runs into the S and O bands. If replacing optics doesn't solve the issue, you'll probably need a test set that can test specifically at 1471 nm. jms