Sometimes fibre optic cables are used for reasons other than lots of bandwidth in architectures other than network A to network B. Examples: 1. transferring d

Sometimes fibre optic cables are used for reasons other than lots of bandwidth in architectures other than network A to network B. Examples: 1. transferring data near/from/to high voltage lines, without risking short circuits that cause fire/death/damage (personal experience: getting info in/out of particle accelerators that hold mega volts of tension) 2. using fibre optic cables to measure vibration or deformations (using the fibre as sensor) 3. physical layer redudancy in case of failure 4. keeping safety critical systems physically seperate from other data transfers There are probably more reasons that are possibly more on-topic. I'm definitely not a fiber applications expert.