Homojunction lead-tin-telluride diode lasers with increased frequency tuning range

Homojunction lead-tin-telluride (Pb1-xSnxTe) diode lasers with a CW frequency tuning range of 216 cm^-1(near m) were fabricated from a Te-rich, ingot-nucleated crystal. The increased frequency tuning range is attributed to a reduced threshold Current density, which allows a higher operating temperature. At a heat-sink temperature of 11.2 K, the threshold current density (Jth) is 212 A cm^-2. The highest heat-sink temperature recorded for these lasers is 61 K with a corresponding Jthof A cm^-2. The longest, continuous current tuning (at 17 K) of one mode is 2.4 cm^-1. At a constant current, the temperature tuning of the same mode is 0.9 cm^-1. The lasers generally emit a single mode for current levels below 125 percent of Jth. Single-mode, single-ended output powers up to 0.9 mW have been recorded.