A steerable-light-path optical device includes a light transceiver having an external light path associated therewith, and a path-steering device that controls the direction of the light path relative to a steering axis. The path-steering device has a first beam-deviation optical element including a first prism structure having a first diffraction grating thereon, and a second beam-deviation optical element including a second prism structure having a second diffraction grating thereon. The steering axis passes through the first and second beam-deviation optical elements. A rotational drive is operable to rotate at least one of the first beam-deviation optical element and the second beam-deviation optical element, and preferably both of the beam-deviation optical elements, about the steering axis.