Improved LPE techniques for low threshold lasers at 1.55 μm in the quaternary In-Ga-As-P/InP system

Improved LPE techniques are described which have resulted in very low threshold current lasers at λ = 1.55 μm in the In-Ga-As-P/InP quaternary system. Close control of growth is achieved by a semi-automated system and uniform sub-micron layers have been grown. The absence of any meltback coupled with the use of a quaternary buffer layer has produced very smooth surfaces and subsequently grown structures have shown markedly improved broad area laser characteristics in terms of yield and uniformity.