Design and fabrication of lead-based fluoride glass channel waveguides

Channel waveguides, when doped with rare-earth ions, are attractive for integrated optics devices (amplifier, microlasers). This paper describes rare-earth doped lead-based fluoride glass channel waveguides produced via mechanical profiling, photolithography (chemical etching and lift-off) and photoinscription using ultraviolet induced refractive index change. The lead-based fluoride glasses belong to the PbF2-ZnF2-GaF3 system, which is, to our knowledge, the only system that allows fluoride glasses to be prepared by vapor phase deposition. The geometry of the channel waveguides has been investigated by using an optical microscope; the near field pattern and optical loss have been measured. The different techniques were compared and the best geometrical confinement was obtained with the 'lift-off' process; the smallest channel width was 5 mu m. The propagation loss varied from 6 to 9 dB at 1480 nm. (C) 1999 Elsevier Science B.V. All rights reserved.