The　characteristics　of　InGaAs　quantum　dot　laser　diodes　have　been　investigated　by　inserting　InGaAs　wells　of　different　thicknesses　in　the　active　zone.　The　simulation　results　indicated　that　the　maximum　output　power　of　the　InGaAs　quantum　dot　laser　diode　with　a　0　nm-thick　InGaAs　well　is　0.72　W　at　an　injection　current　of　1.1　A.　However,　the　quantum　dot　laser　diode　with　a　12　nm-thick　InGaAs　well　has　a　maximum　electro-optical　conversion　efficiency　of　40.6%.　The　properties　of　carrier　transport　in　the　active　zone　were　analyzed　via　the　potential　difference　of　the　band　offset　among　potential　barrier,　potential　well,　and　waveguide　layer.　It　is　observed　that　electron　leakage　increases　owing　to　the　inserted　InGaAs　well.　Auger　recombination　not　only　increases　the　carrier　injection　efficiency　but　also　is　acts　as　the　key　factor　of　carrier　loss　in　the　active　zone.　Moreover,　the　inserted　InGaAs　well　can　improve　carrier　transport　in　the　active　zone　and　increase　the　carrier　utilization　efficiency.　The　power-loss　mechanism　of　the　quantum　dot　laser　diode　was　elucidated　from　the　optical　and　carrier　losses.　It　is　found　that　optical　loss　is　the　key　factor　that　affects　the　output　power.