Complex sentence: The problem is particularly relevant with regards to fiber optic cables-particularly in oil and gas wells where fiber optic cables are used for Distributed temperature sensing the presences of hydrogen can be common due to the cracking of hydrocarbons in the well.
Split into simpler sentences: The problem is particularly relevant to fiber optic cables-particularly in oil and gas wells where fiber optic cables are used for Distributed temperature sensing. Hydrogen can be present due to the cracking of hydrocarbons in the well.