High-speed operation of single-mode tunable quantum cascade laser based on ultra-short resonant cavity

We have demonstrated a room temperature, low power consumption, high-speed, and single-mode tunable quantum cascade laser at λ ∼ 4.6 µm. Combining a 300 µm buried hetero-structure ultra-short cavity with optimized facet coatings, a single-mode tuning range covering ∼40 nm is obtained at room temperature under low electrical power consumption below 1.1 W. The single-mode emission is observed with more than 25 dB side mode suppression ratio in the whole tuning range. The high frequency modulation is achieved with a microwave package, resulting in the −3 dB cutoff frequency of 5.6 GHz.