Quantum cascade lasers with monolithic air–semiconductor Bragg reflectors

Electrically pumped GaAs/AlGaAs quantum cascade lasers with monolithic one-dimensional photonic-band gap mirrors are presented. The mirrors consist of two, precisely defined grooves trenched across the laser ridge using a focused ion beam. A substantial improvement of the laser performance is achieved due to the increased reflectivity of these mirrors. A decrease of the threshold current by 40% at 150 K is observed. The maximum operation temperature increases from 155 K for an unmodified laser to 170 K for the laser with the modified mirrors, and an increase of the T0 parameter from 99 to 114 K is found.