You're showing optical receive power of -40 dBm. That typically means you're not getting any signal. Top thing to check is if the fibers in the connection might be reversed somewhere (change the Rx & Tx fibers). If that doesn't fix it, you'll want to check for broken cables or missed patch points in between. Basically, the range you want to be in is somewhere between the high warn threshold and the low warn threshold (so below -1.0 dBm and above -26.0 dBm). That's a pretty wide range, and with good cables/connectors and legal distances shouldn't be a problem to hit.
If you're running higher power single mode interfaces, you can buy fiber attenuators to reduce the received signal strength, and patch them in it if it's too "hot" (above high warning).
