Three- and four-layer LPE InGaAs(P) mushroom stripe lasers for λ = 1.30, 1.54, and 1.66 µm

Mushroom stripe (MS) InGaAsP/InP and InGaAs/InP lasers have been realized emitting at
\lambda = 1.3, 1.54,
and 1.66 μm, respectively. The main advantage of these MS lasers is their technological simplicity, because only one epitaxial growth step consisting of three or four layers, respectively, is required. No contact layer and no filling layers are needed. In our phosphorus silicate glass (PSG) passivated MS lasers, current spreading is completely inhibited. The devices have very low CW threshold currents and high values of output power, external differential efficiency, and T
o
. All these properties are equivalent to those of the much more complicated buried heterostructure lasers. CW operation in up-side-up mounted MS lasers on p-type substrates is easily achieved, because their series resistance is very low. The devices oscillate in the fundamental lateral mode for easily achievable width and thickness combinations, and tend to longitudinal monomode behavior at moderate output powers. The modulation capability is more than 1 Gbit/s RZ due to the low capacitance of the mushrooms. The commonly used antimeltback layer for lasers with
\lambda > 1.5 \mu
m on