Coupling coefficient calculations for lead-tin telluride distributed feedback lasers

Coupling coefficient calculations of the type originally published for gallium arsenide distributed feedback (DFB) lasers are here extended to the lead-tin telluride based family of devices. Specific calculations of the coupling coefficient as a function of active region and grating dimensions are presented for PbTe/Pb
1-x
Sn
x
Te/PbTe devices,
x = 0.13
and
x = 0.18
, at 8 K and 77 K, and the implications of the results for device design and fabrication are discussed.