[[abstract]]We have established an in situ technique, the strain-induced lateral-layer ordering (SILO) process, whereby lateral composition modulation perpendicular to the growth direction occurs spontaneously during growth by gas source molecular beam epitaxy, producing lateral quantum wells. We have combined this new growth technique with standard quantum well laser growth technology to produce GaInP/AlGaInP strained multiple quantum wire (MQWR) heterostructure lasers. Transmission electron microscopy confirms the presence of laterally ordered MQWR arrays with a linear density of 106 cm-1. Emission spectra from these MBWR heterostructures exhibit quantized energies and significant polarization anisotropies. Photoluminescence emission ener...