Continuous-wave distributed Bragg reflector quantum cascade lasers with fine single-mode tuning up to 102?C at ?? 8.4?m

We have demonstrated an 8.4 mu m stable single-mode quantum cascade laser using a two-section distributed Bragg reflector design. Output power of 252 mW, a threshold current density of 1.04 kA/cm2, and a characteristic temperature of 206 K were achieved during continuous-wave operation at room temperature. Robust single-mode emissions with all side-mode suppression ratios exceeding 25 dB were obtained at injection currents ranging from 420 mA to 900 mA and heat-sink temperatures ranging from 10 degrees C to 102 degrees C. Benefiting from the physical isolation of the two sections and from being mounted epilayer-side down on patterned submounts, the tiny tuning coefficients of the device are -0.003014 cm-1mA-1 and -0.0762 cm-1K-1. This type of single-mode quantum cascade laser with fine tuning characteristics is required to perform accurate detection of trace gases.