Abstract: Hydrogen absorbing mixtures for protecting optical fibers from damage by hydrogen and optical fiber telecommunication cables containing such a mixture or mixtures. The mixture includes at least one oxide selected from oxides of titanium, vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, cerium, tin, lead and wolfram, at least one catalyst selected from among the transition metals, the inorganic and organic compounds of the transition metals and the complexes of the said transition metals, both by themselves as well as supported by inert materials, and an anhydrous salt which, on chemically reacting with water, forms crystalline hydrated compounds which are stable at temperatures up to at least 90.degree. C. The anhydrous salt may be one or more of anhydrous calcium sulfate, anhydrous calcium chloride, anhydrous sodium sulfate and anhydrous copper sulfate.