Transverse　micro-stack　semiconductor　laser　bars　are　put　forward　to　improve　the　output　optical　power　of　semiconductor　laser　bars　at　low　injection　current.　Micro-stack　tunnel　regeneration　tri-active　region　laser　structure　was　grown　by　metal　organic　chemical　vapor　deposition　(MOCVD)　and　laser　diode　bars　with　50%　fill　factors　were　fabricated.　Experiments　show　that　the　insulated　recesses　strongly　affect　the　properties　of　the　bars.　When　the　recess　depth　is　less　than　1.13　mu　m,　the　bars　do　not　work　well.　By　optimizing　the　insulated　recess　depth,　threshold　current　can　be　reduced　to　7.05　A,　the　optical　power　exceeds　79　W　under　50　A　driving　current　and　the　slope　efficiency　reaches　1.81　W/A.　(c)　2008　Elsevier　Ltd.　All　rights　reserved.