Radiation Response of Large Core Polymer Clad Silica Optical Fibers

The radiation-induced optical losses in a selected group of large diameter polymer-clad silica (PCS) optical fibers has been measured in both steady state and pulsed radiation environments. Fibers typically were fabricated from radiation resistant synthetic silicas and silicone polymer materials. Measurements were made in situ at room temperature for operational wavelengths of 0.82μm and 0.92μm. Both growth and decay characteristics of the optical degradation were investigated. As a class, these fibers represent the most radiation resistant optical waveguides measured to date in the laboratory. Radiation-induced optical losses were in general lower at the longer wavelength but the response of all fibers was extremely nonlinear and complex with an important parameter being previous radiation history. For applications that do not require extremely low loss or ultra-high bandwidth but which demand radiation hardness, these large core PCS fibers must be considered as the most attractive candidates available to the systems' designer.