A series of novel highly fluorinated aromatic-aliphatic copolyethers have been prepared by copolycondensation reactions of decafluorodiphenylsulfone (DFPSO) with hexafluorobisphenol-A (6F-BPA) and a highly fluorinated linear or branched diol (6C(F)-diol or 7(b)C(F)-diol) at different feed ratios of [diol]/[6F-BPA]. The reactions can be completed in 2-5 h in the presence of CsF in DMAc at room temperature to produce polymers with number average molecular weight (M-n) up to 45 000 Da. H-1 and F-19 NMR studies show that the composition of the resultant polymers agrees well with the feed ratio of the monomers in the reaction. This feature leads to a feasible tune of glass transition temperatures (T-g) and refractive indexes of the produced polymers by a simple control of the feed ratio. As the [diol]/[6F-BPA] ratio increases, the T-g of the copolymers decreases gradually from 185 to 87 degrees C and 94 degrees C, and the refractive index decreases from 1.5120(n(TE))/1.5089(n(TM)) to 1.4643(n(TE))/1.4629(n(TM)) and 1.4487(n(TE))/1.4471 (n(TM)) for the copolymers from 6C(F)-diol and 7(b)C(F) diol, respectively. Meanwhile, the increase of the [diol]/[6F-BPA] ratio also effectively reduces the birefringence of the polymer films from 3.1 x 10(-3) to 1.4 x 10(-3) for the polymers from 6C(F)-diol and to 1.6 x 10(-3) for the polymers from 7(b)C(F)-diol. Well-developed waveguide structures with smooth ridge walls from these polymers have also been demonstrated using a cost-effective soft lithography technique.