Popular hacker Kevin Mitnick demonstrates how easy it is for an attacker to tap into a network to steal sensitive data, access emails, even if its a fiber optic network. Mitnick used in his attack an optic fiber clip-on coupler that provides non-invasive bi-directional coupling into 250 micron coated single-mode fibers. The hackers can easily tap without cutting the wire by using alligator clips to attach to the cable or they can cut the cable and plug both ends into a small hub.”]
Source: https://securityaffairs.co/wordpress/37987/hacking/kevin-mitnick-hack-fiber-optic.html