An InAlAs native oxide is used to replace thep-nreverse-biased junction in a conventional buried heterostructure InP-based laser. This technique reduces the number of regrowth steps and eliminates leakage current under high-temperature operation. The InAlAs native oxide buried heterostructure (NOBH) laser with strain-compensated InGaAsP/InP multiple quantum well active layers has a threshold current of 5.6 mA, a slope efficiency of 0.23 mW/mA, and a linear power up to 22.5 mW with a HR-coated facet. It exhibits single transverse mode with lasing wavelength at 1.532 &mgr;m. A characteristic temperature(T0)of 50 K is obtained from the NOBH laser with a nonoptimized oxide layer width. ©1998 American Institute of Physics.