UV-written gratings in germanosilicate-glass optical fibers and film waveguides

Diffraction gratings were fabricated both in optical slab waveguides and in optical fibres by irradiation with KrF excimer-laser pulses. Preliminary results are presented for the waveguide gratings, written in germano-silicate glasses and films. Arrays of in-fibre Bragg gratings were produced by using the phase mask method and an improved stretch-and-write technique. A purposely designed apparatus is described, which allows us to write spectrally well separated as well as concatenated grating arrays: both these kinds of structures can find applications as passive components in telecommunication systems.