In　the　optical　current　transformer　the　sub-wavelength　metallic　gratings　are　hopeful　to　substitute　the　traditional　polarizer　because　of　their　excellent　optical　properties.　In　this　paper,　a　powerful　analysis　and　design　tool　used　for　the　sub-wavelength　grating　is　proposed　based　on　Matlab　and　LabVIEW　virtual　instrument　software　architecture.　The　RCWA　(coupled-wave　analysis)　accompany　with　the　enhanced　transmittance　matrix　approach　and　the　method　of　Fourier　factorization　is　applied　for　the　analysis　of　the　grating.　In　the　software　platform,　the　users　can　visually　and　simply　design　a　grating　with　arbitrary　groove　profile　or　intelligently　extract　the　groove　profile　from　the　grating　actually　produced　by　image　processing.　The　values　of　the　diffraction　efficiency　and　grating　extinction　ratio　depend　on　the　various　parameters　of　the　grating　and　incident　light　can　be　analyzed　through　the　results　in　the　form　of　charts　and　tables.　(C)　2011　Published　by　Elsevier　Ltd.　Selection　and/or　peer-review　under　responsibility　of　the　organizing　committee　of　2nd　International　Conference　on　Advances　in　Energy　Engineering　(ICAEE).