The　principle　of　tunnel　regeneration　is　used　to　raise　the　optical　output　power　of　semiconductor　lasers　at　lower　injected　current.　The　optical　modes　are　analyzed　through　the　transfer　matrix　method　for　the　tunnel　regeneration　semiconductor　laser　with　four　optical　coupled　active　regions.　It　is　shown　that　TE3　should　be　the　lasing　mode,　and　there　exists　an　optimum　thickness　for　the　inner　cladding　layers.　Devices　with　inner　cladding　layer　thickness　of　0.3　μm,　0.5　μm　and　0.7　μm　are　epitaxially　grown　by　metal　organic　chemical　vapor　deposition　method　(MOCVD),　respectively.　The　device　with　0.5　μm　inner　cladding　thickness　exhibits　the　best　P-I　characteristics,　the　optical　power　exceeds　5　W　under　2　A　driving　current　without　facet　coating,　and　the　slope　efficiency　reaches　2.74　W/A.　The　results　show　that　the　thickness　of　the　inner　cladding　layers　should　be　designed　properly　so　that　a　higher　optical　output　power　can　be　obtained.