Distributed Bragg-reflector Pb<inf>1-x</inf>Sn<inf>x</inf>Te/PbSe<inf>y</inf>Te<inf>1-y</inf>diode lasers

Abstract

Distributed Bragg-reflector (DBR) diode lasers were designed and fabricated from lattice-matched Pb <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-x</inf> Sn <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">x</inf> Te/PbSe <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">y</inf> Te <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1-y</inf> single heterostructures grown by liquid-phase epitaxy. These DBR lasers operated in a single longitudinal mode within a limited range of heat-sink temperatures, 8.5-38 K, with a threshold current density of ∼3 kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at 20 K. Single longitudinal mode operation was maintained up to more than three times the threshold current. Continuous tuning of the laser output frequency over a range of ∼6 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> , near 775 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> (12.9 μm), was acheived by varying the heat-sink temperature. The average tuning rate was 0.21 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> /K, and it was much smaller than the rate for corresponding Fabry-Perot lasers, which was 2.3 cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-1</sup> /K. The measured effective mode index of the DBR lasers agrees well with the calculated one.