High quality long‐wavelength InGaAsP/InP lasers were grown by atmospheric organometallic vapor phase epitaxy using tertiarybutylarsine (TBA) as a substitute for AsH3. Electrical and photoluminescence measurements on InGaAs and InGaAsP showed that TBA‐grown material was at least as good as AsH3material in terms of suitability for lasers. From two wafers grown by TBA, current thresholdsIthas low as 11 mA were obtained for a 2‐&mgr;m‐wide semi‐insulating blocking planar buried heterostructure laser lasing near 1.3 &mgr;m wavelength. The differential quantum efficiencies &eegr;Dwere as high as 21%/facet with a low internal loss &agr;=21 cm−1. In additionIthas low as 18 mA and &eegr;Das high as 18% have been obtained for multiplequantum well lasers at 1.54 &mgr;m wavelength. These results show that TBA might be used to replace AsH3without compromising on laser performance.