In-plane　optical　anisotropy　(IPOA)　in　modulation-doped　(001)　GaAs/AlGaAs　quantum　wells　(QWs)　has　been　studied　by　reflectance　difference　spectroscopy　(RDS).　By　changing　the　position　of　the　delta-doping　layer,　we　introduce　an　asymmetric　potential　into　the　quantum　well　system,　which　results　in　an　additional　IPOA.　Compared　to　symmetrically　doped　and　undoped　structure,　the　asymmetrically　doped　QWs　exhibit　larger　IPOA,　which　is　clearly　demonstrated　both　by　the　RDS　results　measured　at　80　K　and　the　linear　extrapolation　of　the　RDS　signal　under　uniaxial　strain　measured　at　room　temperature.　Numerical　calculations　within　the　envelope　function　framework　show　that　the　asymmetric　potential　induced　by　asymmetrically　doping　will　introduce　additional　hole-mixing　coefficients.　This　work　demonstrates　that　the　IPOA　of　QWs　can　be　tailored　by　changing　the　delta-doping　position.　(C)　2013　American　Institute　of　Physics.　[http://dx.doi.org/10.1063/1.4790577]