Extremely uniform and high-densityGaAs/(GaAs)4(AlAs)2quantum wires (QWRs) were self-organized in a thinGaAs/(GaAs)4(AlAs)2quantum well grown on a (775)B GaAs substrate with a regularly corrugated AlAs–on–GaAs interface and a flat GaAs–on–AlAs interface by molecular beam epitaxy. A strong photoluminescence (PL) peak at &lgr;=692 nm from the GaAs/(GaAs)4(AlAs)2QWRs showed large polarization anisotropy[P=(I∥−I⊥)/(I∥+I⊥)=0.19]. A full width at half-maximum of the PL peak from the QWRs was as small as 15 meV at 14 K, which is smaller than those of any self-organized GaAs/AlGaAs QWRs reported so far. Density of the QWRs (8×105QWRs/cm) is the same as the highest ever reported. These results indicate that the QWRs grown on the (775)B GaAs substrate meet requirements for applications to QWR lasers (high uniformity, high density, high optical quality, and simple fabrication process). ©1997 American Institute of Physics.