Transmission loss of coated single-mode fiber at low temperatures

Coated single-mode fibers with various coating thicknesses were manufactured, and loss increases due to cooling were measured. It was found that the excess loss increases steeply in the small V-value region at low temperatures. A simple model for fiber bends in the coating was introduced, and the increases in loss were related to the strain resulting from use of the model. It would appear that the axial compressive strain has a serious influence on the loss increases. A suitable silicone buffer layer for preventing loss increases has been determined. The selected silicone layer diameter is 0.45 mm for a 0.9-mm nylon outer layer diam.