PbSnTe/PbTe double hetero-diode structures were grown by temperature difference method under controlled vapor pressure (TDM–CVP) liquid-phase epitaxy (LPE). These laser diode (LD) structures were of the PbTe (Bi)/Pb 1−x Sn x Te/PbTe (undoped substrate) double hetero (DH) type. The peak shift of the wavelength emitted by the fabricated diodes was recorded and it was found that they successfully lased from 15K to over 77K (liquid nitrogen temperature) at a slightly lower threshold current density than standard LPEs fabricated via the slow-cooling method. In addition, the lasing peak wavelength was longer than spontaneous emissions. The laser spectra of diodes with varying Sn concentrations (x) in the active layer were observed, and their intensities were recorded as a function of the wavelength. Very sharp lasing spectra were obtained between 6.5μm and 9.4μm (x=0–0.11), clarifying that the stoichiometry control possible with TDM–CVP is suitable for fabricating optical devices. In addition, it was demonstrated that TDM–CVP is appropriate for fabricating infrared optical devices constructed from Pb x Sn 1−x Te systems.