Surface-relief gratings with submicrometer modulation periods were ablated by F₂-laser radiation in thin metal-oxide films to produce resonant grating waveguide structures. For 150\text{\hspace{0.17em} nm} films of {\text{Nb}}_{\text{2}}{\text{O 5}}_{} , grating amplitudes in the range of 5– 50\text{\hspace{0.17em} nm} could be reproducibly excised with a controlled exposure of a laser energy density and a number of pulses within a narrow processing window. Resonant coupling of \text{800 \hspace{0.17em} nm} ultrashort pulsed laser light into the resulting grating waveguide structure is verified with reflection and transmission spectra and satisfactorily modeled by coupled-mode theory. The laser-fabricated grating waveguides are attractive for high damage threshold reflectors and biosensor applications.