Recent progress in reducing the extrinsic losses of fluorozirconate optical fibers has increased the material research efforts for these new waveguides. Fluorozirconate fibers, which are inherently more transparent than silica fibers, are predicted to have intrinsic losses as low as 0.001 dB/km at 3.45 μm [11]. Unfortunately, high intrinsic losses still plague these new optical fibers and these losses must be understood before ultra-low loss fibers become a reality. An automated fiber optic characterizer can help determine the loss mechanisms and the optical properties of fluorozirconate fibers so extrinsic loss mechanisms can be understood and eventually controlled. The automated fiber optic characterizer can also speed up the measurement process by using a microcomputer to align the fiber, calculate the results, and plot the graph. This thesis presents the technical issues involved in the design and construction of an automated infrared fiber optic characterizer. The thesis also outlines the test results of a constructed automated fiber optic characterizer. The characterizer measures spectral attenuation between 0.8 μm and 4 μm, differential modal attenuation between 1.6 μm and 4 μm, and numerical aperture at 1.55 μm and 2.55 μm. / Master of Science