Distributed feedback quantum cascade lasers at 13.8 mu m on indium phosphide

We report on the growth, processing, and characterization of distributed feedback quantum cascade lasers emitting in single mode at 13.8 mu m. Lasers were grown in the indium phosphide material system with a bound-to-continuum active region and processed as double channel ridges with metalized top grating. Electro-optic characteristics as well as current and temperature tuning are investigated. Maximum single mode peak powers exceeding 800 mW at room temperature and intrapulse-tuning covering 3 cm(-1) for a gas absorption experiment are demonstrated. Furthermore data on the far field are presented showing a slow-axis divergence angle of 28.3 degrees full width at half maximum). (C) 2011 American Institute of Physics. [doi: 10.1063/1.3593499]