1.3 mu m InAlGaAs strain-compensated multiple-quantum-well lasers without any phosphor-containing layers in the epitaxial structure have been grown by solid-source molecular-beam epitaxy (MBE). Substrate temperature was found to be a critical growth parameter for lattice-matched InAI(Ga)As layers in the laser structures. In the temperature range of 485-520 degrees C, spontaneously ordered superlattices (SLs) with periods around 7-10 nm were formed in the bulk InAI(Ga)As layers, as evidenced by x-ray diffraction measurements. Based on photoluminescence (PC) measurements, a large band gap reduction of 300 meV and a broadened PL peak were observed for the In0.52Al0.48As layers with SL as compared to those without SL. The undesirable spontaneously ordered SL can be avoided in MBE growth with temperatures higher than 530 degrees C, resulting in a high laser performance. Threshold-current density as low as 690 A/cm(2) and T-0 as high as 80 K were achieved for InAlGaAs laser bars emitting at 1310 nm. (c) 2007 American Vacuum Society.