Single-mode PbSnTe laser with a buried heterostructure

A Pb(1-x)Sn(x)Te single-mode laser with a buried heterostructure has been developed by use of a two-step liquid-phase epitaxial growth. The active-layer size was calculated for fundamental transverse-mode operation. Tin diffusion was simulated in the active layer during the second growth step, and the results were used to select the optimum growth temperature. Analysis of the crystal-growth mechanism in the buried-heterostructure formation enabled us to develop a new growth method. The laser we developed showed single-mode operation with a wavelength of 8 µm and a power of 1.7 mW at 50 K. At 80 K, the threshold current for continuous-wave (cw) operation is 60 mA, which is nearly equal to the threshold current for pulsed operation. Maximum operating temperatures are 105 K for cw operation and 144 K for pulsed operation.