There are many reasons for the excessive attenuation of optical fibers,
Firstly, the leader did not connect properly,
Secondly, the first and second parts of the optical fiber are not fused properly (this is not due to the installation personnel)
Thirdly, the light output from the computer room is too large (under normal circumstances, the light output from the computer room is between+2 and+5, and it is not available when there are small and+2 or negative numbers)
Fourthly, there is excessive bending of the optical fiber during the laying process (dead angles, excessive bending, etc.)
Fifth: The output of the splitter is too large (if the input of the splitter is -8 and the output is -20, it is considered that the output is too large)
Sixth: The middle joint of the optical cable is not fused properly, (the joint box is not fused properly, bubbles appear during the fusion process of the optical fiber, and the light attenuation is too large, etc.)
thanks