Microstructured polymer optical fibers (mPOF) probably have the widest range of possible fabrication methods, bring as they do the diversity of polymer processing techniques, including casting, molding, and extrusion. The draw process for microstructured fibers is essentially the same as that used for other optical fibers. A major challenge in making microstructured fibers in any material is to make the preform. The integrity of the capillary stack requires the packing to be very tight, in order to avoid later deformation, and may also be improved by pressurizing and/or collapsing various sections of the preform. As with one optical fiber, modeling Microstructured optical fibers involves solving Maxwell’s equations for the appropriate fiber geometry, and with correct boundary conditions. Most conventional fibers use a refractive index contrast between core and cladding which is relatively small. Different from POFs, single-mode mPOFs exhibit polarization properties that make them potentially interesting for their use in the design and development of polarimetric-based sensors.