Fluorinated hyperbranched polymers and dendrimers with low optical losses and functionality to modify refractive index and add a cross-linking unit were developed. The results of refractive index measurements indicate a tunability of the refractive index between approximately 1.5 and 1.6, and optical losses below 0.5 dB/cm at 1550 nm. Dendrimers with similar surface group structure and possibility to surface functionalization were prepared using a lanthanide cation as focal point. Results on luminescent properties in the NIR and IR regions were measured for lanthanide ions such as Nd3+ and Er3+, showing characteristic emission bands at 1.06, 1.3 and 1.5 µm. The associated absorption and excitation spectra were found similar to those of the corresponding ions in optical glasses. © 2002 Elsevier Science B.V. All rights reserved.