We describe InGaAsP inverted rib waveguide lasers emitting at 1.54 &mgr;m with pulsed current thresholds as low as 60 mA, external quantum efficiencies of up to 0.2 per facet, and emitting 16 mW in the lowest order. Pulsed operation to 110 °C withT0values of 50–72 °C were obtained. For continuous operation at 15 °C up to 21 mW per facet was observed with external quantum efficiencies of 0.15 per facet andT0up to 62 °C. The maximum continuous operating temperature was 55 °C and was determined by heating of the junction.