A　seven-point-defect　photonic　crystal　(PhC)　vertical　cavity　surface　emitting　laser　(VCSEL)　operating　with　high　single-fundamental-mode　of　23　mW　and　low　threshold　current　of　1.2　mA　was　demonstrated　and　its　performance　was　analyzed.　The　single-fundamental-mode　emission　aperture　(central　defect　area)　was　enlarged　to　achieve　high　output　power.　Furthermore,　suitable　refractive　index　step　due　to　the　photonic　crystal　structure　was　obtained　to　overcome　the　external　index　perturbations,　which　can　be　attributed　to　stable　single-fundamental-mode　operation　even　at　saturation　current.　The　transverse　mode　confinement　characteristics　by　photonic　crystal　was　analyzed　based　on　the　effective　index　model　and　showed　good　agreement　with　the　experiment　results.　(c)　2013　Elsevier　Ltd.　All　rights　reserved.