InGaAsP laser with high T0

We report measured T
0
values as high as 127 K for 1.3 μm InGaAsP buried heterostructure lasers. An analysis of the electrical characteristics of high T
0
lasers indicates the presence of shunt leakage currents. The actual T
0
of the current flowing through the active layer junction is shown to be 70 ± 10 K. The observed reduction in threshold temperature sensitivity may be useful in some applications.