Abstract: A laser doppler velocimeter system for wind shear detection comprising means for generating a beam of radiant energy, an optical system coupled to the beam for directing a first portion of the beam a predetermined distance to a scatterer of radiant energy, means coupled to the beam for conducting a second portion of the beam through a polarization preserving medium, the length of the medium substantially matching the predetermined distance, means for mixing the second portion of the beam with the radiant energy reflected by the scatterer and means coupled to the means for mixing for measuring a component of the velocity measurements of the scatterer. The velocity includes both horizontal and vertical components. The system may also be adapted for measurement of multiple predetermined distances by using multiple means for conducting a second portion of the beam, each of said multiple means having a length substantially matching one of the multiple predetermined distances.