Micromachined passive waveguide fabrication with fs laser in Ag-doped GeO2-PbO glasses for photonics: straight, curved and Y shaped configurations

This study aims to produce and characterize different dual waveguides using femtosecond (fs) laser irradiation on GeO2-based glass samples. The work is motivated by previous results obtained with rare earth ions doped GeO2 - PbO glass, with and without silver nanoparticles, in which irradiation, with fs laser was successful. The work aims to manufacture different structures such as straight, curved, and Y waveguides (using the double guide configuration) for applications in photonics (resonant rings, beam splitters, among others) in GeO2 - PbO glasses with silver nanoparticles. For both, straight and S curved waveguides, better M-2 (beam quality factor) results were found for a distance between the guide walls of 10 mu m, when compared to 25 mu m. Moreover, among the two different curved guides produced it was also possible to observe better guidance when a larger radius of curvature (20 mm) was used; preliminary tests showed no guiding for 5 mm and 10 mm radius. The highest relative propagation loss was obtained for the S curved waveguide with a 25 mu m distance between the guide walls whereas the lowest one was found for the Y shaped waveguide; for this configuration (opening angle of 5 degrees and distance of 620 mu m between the two arms) an output power ratio between the left and right arm of 53.9/46.1 showed promising applications for beam splitters.