The In-line Polarizer is designed to pass light with one specific polarization while blocking the other polarization. It can be used to convert no-polarized light into polarized light with high extinction ratio. It can also be used to enhance the extinction ratio of signals with its polarization properties. We offer all possible fiber coupling combinations: PM to PM, SM to PM, SM to SM. High power version is also available in which a third port is added to guide the unwanted light out. Our design minimizes component assembly costs and module footprint while increasing stability over a wide temperature and wavelength ranges.