Abstract: A modified Michelson type of interferometer having a pair of substantially identical refractive prisms, each having a cross sectional shape of 1/2 of a hexagon, the division being along a line bisecting opposite sides of the hexagon, where each of the prisms has a side for beam input or output, a side that is coated to provide a mirror for beam reflection and a beamsplitter coating applied to one of the two surfaces along the line of division. Additionally, a collimating and/or focusing lens may be integral with the prism having the input or output side, such that linear, constant speed, relative scanning of the prisms in the direction of the line of division of the prisms enables the elimination of the mounting of all components, made a part of or attached to the prisms, to an optical bench.