In0.1Ga0.9As/(GaAs)(6)(AlAs)(1) quantum wires (QWRs) were naturally formed in a 3.0-nm- or 4.8-nm-thick In0.1Ga0.9As/(GaAs)(6)(AlAs)(1) quantum well grown on a (775)B-oriented GaAs substrate by molecular beam epitaxy which has a corrugated A1As-on-InGaAs upper interface (a period of about 40 nm and a vertical amplitude of about 2 nm) and a flat InGaAs-on-AlAs lower interface. Strong polarization dependence [P drop (I-\\ - I-perpendicular to)/(I-\\ + I-perpendicular to) = 0.15] of photoluminescence spectrum from the (775)B InGaAs QWR structures (L-w= 3.0 nm) was observed at 11 K, indicating their good one dimensionality. Graded index separate confinement heterostructure-type self-organized (775)B In0.1Ga0.9As/(GaAs)(6)(AlAs)(1) QWR lasers were fabricated, and they showed laser oscillation with threshold current densities of 1.7-3.1 kA/cm(2) and lasing wavelengths of 833-868 nm at room temperature (27 degrees C) under pulsed current condition.