In　this　paper,　a　protocol　for　single-photon-assisted　entanglement　concentration　is　proposed.　Resorting　to　the　nonlinear　optics　of　a　nitrogen-vacancy　(NV)　center　in　a　diamond　embedded　in　a　photonic　crystal　cavity　coupled　to　a　waveguide,　remote　parties　can　share　the　maximally　entangled　photon　pair　with　a　certain　probability.　Compared　with　other　entanglement　concentration　protocols　(ECPs),　the　current　one　does　not　need　to　know　the　accurate　coefficients　of　the　initial　state　and　can　be　repeated　to　get　a　higher　success　probability.　Meanwhile,　this　protocol　is　more　suitable　for　multiphoton　system　concentration.　All　these　advantages　make　the　protocol　useful　in　long-distance　quantum　communication.　(C)　2014　Elsevier　B.V.　All　rights　reserved.