ORIGIN OF HIGH-BANDWIDTH PERFORMANCE OF GRADED-INDEX PLASTIC OPTICAL FIBERS

Observations in high bandwidth graded-index plastic optical fibers (GI POFs) are reported of strong mode coupling and its characteristic squ are root-like fiber length dependence of the optical pulse broadening. We have further found that the measured refractive index profile is n ot parabolic, but consists of two markedly different regions. Analysis of the index profile reveals that strong mode coupling increases the GI POF bandwidth from its profile-determined value of 0.43 GHz to its measured value of 3.0 GHz for 100 m. (C) 1997 American Institute of Ph ysics. [S0003-6951(97)01651-3].