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Long-wavelength (1.55 $\mu$m) $\rm Ga\sb{x}In\sb{1-x}As/Al\sb{0.48}In\sb{0.52}As$ multiple quantum wire (MQWR) lasers grown on (100) on-axis InP substrates by a single-step MBE have been successfully fabricated and characterized. The QWRs were formed in situ in the (GaAs)$\sb2$/(InAs)$\sb{2.2}$ short-period-superlattice (SPS) layers by the strained-induced lateral-layer ordering (SILO) process. The analysis of cross-sectional and plan-view transmission electron microscopic images, photoluminescence peak energies, and photoluminescence polarization anisotropy has confirmed the QWR formation. The SILO process induced lateral composition modulation occurs over a wide temperature range near 500$\sp\circ$C, and the magnitude of strain accumulates when growth proceeds. A strain-driven bulk solid-state diffusion model is the driving force of the SILO process, instead of the simple surface diffusion model. The 77 K threshold current densities (J$\sb{\rm th}$) for $\rm Ga\sb{x}In\sb{1-x}As$ MQWR laser diodes with laser cavities along the (110) and (110) directions showed an anisotropy ratio of $\sim$10. Due to the directionality of two-dimensional quantum confinement, lasers with cavities along the (110) direction consistently showed a lower J$\sb{\rm th}$ than those along the (110) direction. The typical J$\sb{\rm th}$ for the MQWR laser with the contact stripe perpendicular to the QWRs is 1 kA/cm$\sp2$ at 300 K, which is a 30% improvement when compared with that for the conventional quantum well laser. The temperature dependence of the lasing wavelength from this Fabry-Perot cavity MQWR laser is less than 1 A/$\sp\circ$C between 77 and 300 K. The SILO process induced triaxial strain in the (GaAS)$\sb2$/(InAS)$\sb{2.2}$ SPS active region is responsible for this temperature insensitivity. The lasing wavelengths are about 1.715 $\mu$m and 1.695 $\mu$m at 300 K and 77 K, respectively.
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