| 摘要 |
PURPOSE:To prevent reduction in the transmission characteristics of a cable under radiation and the deterioration of the cores due to a temp. change by placing a heating element in the cable so as to keep the inside of the cable at a prescribed temp. CONSTITUTION:This radiation resistant optical fiber cable has plural optical fiber cores 2 arranged around a central heating element 1 with spacers 3 in- between. Each of the cores 2 is formed by coating a fiber strand consisting of a pure quartz core of 50mum diameter and a clad of 125mum outside diameter with an Si layer of 400mum thickness and a nylon layer of 0.9mm. thickness. High tension ''Kevler'' fibers are used as the spacers 3. The cores 2 are covered with a wound polyester tape 4 for pressing, a cushion layer 5 consisting of ''Kevler'' fibers and a flame retardant polyethylene jacket 6. The inside of the cable is kept at 50-90 deg.C with the heating element 1. |
