Bandwidth enhancement of graded index plastic optical fiber by control of differential mode attenuation.

We propose a novel method of graded index plastic optical fiber (GI POF) to enhance bandwidth. Recently, it has been reported that perfluorinated GI POF with a double cladding structure had much higher bandwidth than theoretical value. The result of analysis of this fiber indicates that the high-bandwidth property is obtained because higher order modes are attenuated at a core and cladding polymer boundary. In addition, it does not induce large increment of attenuation of lower order modes and bending loss. Then, by adopting the rod-in-tube method, we control differential mode attenuation of PMMA based GI POF, and it is proved that bandwidth of GI POF can be enhanced by utilizing scattering of the core and cladding polymer boundary.