A computing device includes an optical network transceiver and a basic input/output system (BIOS). The optical network transceiver is to connect to an optical network and to generate an event indicating that an optical signal strength has attenuated below a threshold. The BIOS is to determine generation of the event by the optical network transceiver, and responsively detect occurrence of a potential optical network intrusion attack. In response to detecting occurrence of the potential optical network intrusion attack, the BIOS is to perform an action to protect the computing device from the potential optical network intrusion attack.