that the following detailed description of various embodiments is by way of example only and is not meant to limit in any way the scope of the present invention as shown in fig1 a collimator according to the invention contains a collimator body 10 and a lens carrier 12 fits within the body 10 and can move in telescoping fashion along a longitudinal axis u201c a u201d common to the body and the carrier a lens carrier nut or sleeve 14 surrounds the lens carrier and a precision adjuster 16 fixed in the collimator body is provided to adjust the position of the lens carrier along the axis an optical cable is connected to the end of the collimator body opposite the lens carrier by means of a fiber optic connector 18 as seen in fig2 the collimator body 10 and the lens carrier 12 are hollow and define chambers 20 and 21 through which optical radiation may pass the lens carrier chamber 21 diverges in the lens carrier toward its open end from left to right in the figure to provide an adequate clear aperture for diverging beams the lens carrier 12 which is inserted into the open bore defining the chamber 20 has a central seat 22 into which a removable lens 23 is inserted an interchangeable fiber optic connector adapter 24 is secured by screws to the collimator body on the side opposite the lens carrier a fiber optic connector 18 connects to the exterior of the interchangeable fiber optic connector adaptor 24 optical energy transmitted through the fiber optic cable is emitted at the fiber optic connector according to the numerical aperture of the specific fiber being used the free space optical energy passes through the aperture in the.