In this work the fabrication of integrated polymer waveguide components (waveguides, S-bends, splitters) by means of several approaches is reported. Fabrication of one type of waveguide involves laser-assisted micro-patterning of small grooves in (Polymethylmethacrylat) PMMA substrates which are subsequently filled with index-matched materials. Another type of waveguide is realized by local physical modification of PMMA in a laser direct writing process. The transmission characteristics of the waveguide were studied at the optical communication wavelengths of 1520-1620 nm. Fabrication of filled waveguides with oil as waveguide medium yielded low loss of 2.6 dB/cm and single-mode behavior for 10 μm wide grooves. Filling of 20 μm grooves with PMMA/MMA/dye mixture and subsequent polymerization yielded multi-mode waveguides with higher loss of 5.9 dB/cm. The laser direct writing (Nd:YAG, 266 nm) of waveguides showed loss of 6.3 dB/cm and multi-mode behavior indicating a need for further process optimization. Two Y-splitters fabricated by laser patterning and filling with branch radii of 10 mm and 25 mm showed device loss of 16 dB and 19 dB for a 25 mm device length. These results are compared to the performance of reference Y-splitters fabricated by UV-lithography, where parametric studies of the device geometry revealed the best branch radius of 20 mm.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.