Fundamental waveguiding properties of amorphous As2S3 film and some applications to passive optical grating devices are presented. The propagation losses of amorphous As2S3 film waveguides were measured to be 4.4 dB/cm at 0.633 ,um and 1.4 dB/cm at 1.153 um. Chalcogenide amorphous semiconductors are characterized by the photoinduced refractive index change. Utilizing this phenomenon, a grating with the period of 0.35 um and the length of 0.7 mm was fabricated in a As2S3 film waveguide as the grating deflector with a two-beam interference technique. A guided wave of 1.153 um, TM0 mode, has been deflected with the deflection angle of approximately 90° and with the efficiency of 100%. With the same technique, a grating coupler with the period of 0.55 um and a slant angle of 10.5° was fabricated, and the coupling efficiency was 1.3% at 1.153 Am.