Segmented-cladding fibers (SCF) consist of a uniform core of high refractive index and a cladding with regions of high and low refractive index alternating angularly, which can effectively realize single mode with a large core diameter. Because polymer optical fibers are usually Of large diameter, theoretical model for SCF was further extended to segmented-cladding polymer optical fibers (SCPOF) doped with rare earth complex in this article. Oil the basis of the physical principle, a material model for SCPOF was established, from which refractive index and glass transition temperature of polymer materials was pre-determined for the core and cladding of SCPOF, respectively. According to the model, a preform for SCPOF was fabricated with the core doped with ELI(DBM)(3)Phen that has characteristic emission at 613 nm under excitation at 365 nm. From results of fluorescence photograph, it is clearly seen that the expected preform has been obtained by a two-step method developed in this work. (C) 2008 Wiley Periodicals, Inc. J Appl Polym Sci 111: 730-734, 2009