Large　scale　optoelectronic　monolithic　integration　for　optical　fiber　communication　makes　more　and　more　optoelectronic　active　devices　and　passive　components　integrate　into　a　single　chip.　It　is　necessary　to　provide　enough　wide　gain　spectrum　to　satisfy　the　requirement　from　each　device.　In　this　paper,　based　the　analysis　on　the　gain　spectrum　of　InGaAsP/InP　quantum　well,　the　dependence　of　its　gain　spectrum　bandwidth　on　the　well　width　and　doping　concentration　was　derived.　An　asymmetric　quantum　well　with　the　same　doping　concentration　and　different　well　width　was　design　to　realize　the　destination.　The　simulation　results　prove　that　the　asymmetric　quantum　well　indeed　make　the　gain　spectrum　wider.　Then　the　asymmetric　quantum　wells　were　grown　successfully　by　low　pressure　MOCVD　at　665　degrees　C.　The　full　width　at　half　maximum　(FWHM)　of　115nm　was　observed　in　its　amplified　spontaneous　emission　(ASE)　spectrum,　which　was　flatter　and　wider　than　that　of　the　symmetric　quantum　wells.