Long haul fibres need EDFAs to boost the optical signal so that it can travel through thousands of kilometers of fibre. EDFAs need laser light to perform ampli

Long haul fibres need EDFAs to boost the optical signal so that it can travel through thousands of kilometers of fibre. EDFAs need laser light to perform amplification. Generating laser light requires electricity. Electricity requires conductive wires. Conductive wires are susceptible to induced currents caused by solar flares over large distances. The IEEE brings this up every few years into relation with the electrical grid. A massive solar flare will likely result in humanity being thrown into chaos for multiple years with large chunks of infrastructure being offline until low volume high cost replacement parts (especially high voltage transformers) are built.