The long-term thermal stability of the attenuation of graded-index plastic optical fibers is strongly dependent on whether the glass transition temperature (Tg) of the cladding layer is higher than the environmental temperature. When fibers are exposed to temperatures higher than both the core and cladding Tg values, the core-cladding boundary fluctuates spatially and scatters light. However, our study indicates that the core is not necessarily required to be in a glassy state to maintain a flat, smooth interface as long as the cladding is in a glassy state.
- Hirotsugu Yoshida
- Ryosuke Nakao
- Yasuhiro Koike
