Frost-resistant fiber optic modules

An investigation was made of the additional losses observed at temperatures from — 120 °C to + 20 °C in fiber-optic modules with different types of polymer cladding. Crystallization of a soft silicone elastomer in the primary cladding resulted in a considerable increase in the optical losses in these modules, irrespective of the nature of the secondary cladding. When a noncrystallizing silicone elastomer was used as the primary cladding and the thickness of the secondary cladding was reduced, it was possible to ensure that the additional losses in a module were low right down to temperatures of — 120 °C.