Quantum Cascade Laser With Unilateral Grating

We report on distributed feedback quantum cascade lasers at a wavelength of 3.58 μm operating at room temperature. Single-mode emission with a side-mode suppression ratio of 30 dB is achieved by manufacturing single-sided third-order lateral gratings. The devices exhibit watt level peak powers with a threshold current density of ~ 4.3 kA/cm
²
at room temperature and remain in single-mode operation over the temperature range of 280-420 K.