High polarization extinction ratio (PER) in-fiber polarizers are essential in various fiber-based technologies. In this letter, we propose and demonstrate an in-fiber dispersion compensated polarizer (DCP) based on integrated fiber gratings, which is fabricated by a UV-inscribed 45° tilted fiber grating (TFG) and a chirped fiber Bragg grating (CFBG) in series. Such compact device could enhance the PER of 45° TFG with nearly double value and it is potential to achieve ultra-high PER with relatively short length and simple fabrication. Meanwhile, DCP could also function as a dispersion management component. Finally, with the integrated grating device, we have demonstrated an all fiber mode-locked laser system, generating soliton pulses at the normal and anomalous dispersion regime, respectively.