Cavity-free　optical　nonreciprocity　components,　which　have　an　inherent　strong　asymmetric　interaction　between　the　forward-　A　nd　backward-propagation　direction　of　the　probe　field,　are　key　to　produce　such　as　optical　isolators　and　circulators.　According　to　the　proposal　presented　by　Xia,　[Phys.　Rev.　Lett.　121,　203602　(2018)]PRLTAO0031-900710.1103/PhysRevLett.121.203602,　we　experimentally　build　a　device　that　uses　cross-Kerr　nonlinearity　to　achieve　a　cavity-free　optical　isolator　and　circulator.　Its　nonreciprocal　behavior　arises　from　the　thermal　motion　of　N-type　configuration　atoms,　which　induces　a　strong　chiral　cross-Kerr　nonlinear　response　for　the　weak　probe　beam.　We　obtain　a　two-port　optical　isolator　for　up　to　20　dB　of　isolation　ratio　in　a　specially　designed　Sagnac　interferometer.　The　distinct　propagation　directions　of　the　weak　probe　field　determine　its　cross-phase　shift　and　transmission,　by　which　we　demonstrate　the　accessibility　of　a　four-port　optical　circulator.　©　2020　authors.　Published　by　the　American　Physical　Society.