Polarization　entangled　photon　pair　source　is　widely　used　in　many　quantum　information　processing　applications　such　as　teleportation,　quantum　communications,　quantum　computation　and　high　precision　quantum　metrology.　We　report　on　the　generation　of　a　continuous-wave　pumped　1550　nm　polarization　entangled　photon　pair　source　at　telecom　wavelength　using　a　type-II　periodically　poled　KTiOPO4　(PPKTP)　crystal　in　a　Sagnac　interferometer.　Hong-Ou-Mandel　(HOM)　interference　measurement　yields　signal　and　idler　photon　bandwidth　of　2.4　nm.　High　quality　of　entanglement　is　verified　by　various　kinds　of　measurements,　for　example　two-photon　interference　fringes,　Bell　inequality　and　quantum　states　tomography.　The　source　can　be　tuned　over　a　broad　range　against　temperature　or　pump　power　without　loss　of　visibilities.　This　source　will　be　used　in　our　future　experiments　such　as　generation　of　orbital　angular　momentum　entangled　source　at　telecom　wavelength　for　quantum　frequency　up-conversion,　entanglement　based　quantum　key　distributions　and　many　other　quantum　optics　experiments　at　telecom　wavelengths.　(C)　2015　Optical　Society　of　America