Continuous-wave distributed-feedback quantum-cascade lasers on a Peltier cooler

Continuous-wave operation of lambdasimilar to9 mum distributed-feedback quantum-cascade lasers is reported up to a temperature of 260 K. Single-frequency emission with a side mode suppression ratio of greater than or equal to27 dB and with a tuning range of 5 cm(-1) between 200 and 245 K (a tunability of -0.078 cm(-1)/K and -0.764 cm(-1)/W) is obtained for the junction-down mounted buried heterostructure devices. Uncoated lasers display an output power of up to 18 mW at 180 K and still 1 mW at 250 K. Lasers with high-reflection coated facets could be operated up to 260 K. (C) 2003 American Institute of Physics.