Optical loss increase in optical fibre coated with silicone resin containing Si-D

One possible origin of the loss increase phenomenon with heat treatment at 200°C (H₂ evolution from the coating material) has been investigated, using optical fibre coated with silicone resin containing the Si-D group. Although OH absorption at 1.4 μm increases with 200°C heat treatment, no OD peak is observed. It is suggested that silicone resin containing no Si-H and Si-CH_{2-CH2-Si groups is appropriate as a coating material as no H2 evolution is present.}