The paper describes preparation and performance of single lateral mode buried heterostructure InGaAsP/InP, &lgr;=1.3 &mgr;m, laser diodes. It is shown that an improvement in the mesa etching and regrowth techniques permits obtaining laser diodes whose threshold current densities are about 1 kA/cm2and are practically independent of stripe width. The diodes thus prepared had threshold currents of 8–20 mA at a cavity lengthL=200–500 &mgr;m and a stripe width about 2–3 &mgr;m. The maximum continuous wave power in single lateral mode operation was 160 mW.