Abstract: An LDV optical system for projecting a two-color, two-axis interference fringe system and collecting backscatter radiation for two component velocity measurement. A rotor within an optical head of the system having a pair of beam splitters and a two-color filter provides two pairs of diametrically opposed split beams in orthogonal planes and with the split beams equidistant from the axis of the rotor and is angularly adjustable for setting the angular orientation of the fringe system. In a modified embodiment, a rotor with a single beam splitter providing a single pair of diametrically opposed split beams is connected to a motor to be rotated between 90.degree. limit positions for two component velocity measurement using two colors for the measurement of each component.