Using an InP lattice matched InGaAlAs/InAlAs system, an all-monolithic vertical laser structure has been grown. Pulsed lasing at 1.56 mu m has been obtained up to +55 degrees C with 45 mu m diameter proton-implanted diodes. A thermal resistance of similar to 420 K/W has been estimated. The reported characterisations indicate the potential of this system laser for CW operation and for simple large-scale processing.