In this paper we present a successful growth of highly strained GaInAs/GaAs quantum wells by low-pressure organometallic vapor-phase epitaxy using tertiarybutylarsine. The transition from uniform to island or dot-like growth mode has been prohibited by carefully choosing the growth condition. Photoluminescence wavelengths of up to 1.2 mu m with a FWHM of 23 meV were obtained. We experimentally determined the maximum well thickness for highly strained GaInAs/GaAs QW of good crystal quality and compared our results to critical thickness models. Transmission electron microscopy measurements were used to discuss the degradation mechanism for highly strained GaInAs layers. Also excellent lasing properties of 1.2 mu m highly strained GaInAs/GaAs quantum well lasers have been demonstrated.