Low RX power is usually caused by dirty fiber connectors, damaged cables, excessive bending of the fiber patch cord, or exceeding the maximum distance of the transceiver. It can also indicate a failing transmitter at the remote end. I've been having issues with my internet speed shooting up to 600mbps only to plummet down to 100mbps within split-second during speedtest. My plan is 2099 which is 400mbps. These networks are the backbone of modern data transmission, offering incredible speeds and bandwidth. However, even the most robust systems can. Fiber optic networks are celebrated for their speed and reliability, but even the best systems can encounter problems. These high-speed, high-capacity communication networks are increasingly replacing copper cables, offering superior performance and. What could be causing high BER? Three things are the most obvious; 1) Is the networking equipment overloaded when operating on a singlemode link with ONLY 2 dB loss or are the transceivers causing problems.