Intersubband and interminiband GaAs/AlGaAs quantum cascade lasers

Electrically pumped injection lasers based on the GaAs/AlGaAs material system are investigated. Intersubband transitions in coupled quantum wells and intraband transitions in a finite superlattice are used to demonstrate lasing. The laser emission wavelength is View the MathML source for the intersubband lasers and View the MathML source for the laser structure having a finite superlattice as an active cell. Utilizing ridge waveguide laser bars at a heat-sink temperature of 10 K, peak optical powers of the intersubband quantum cascade lasers exceed 300 mW (interminiband: 100 mW). The maximum operating temperature is 160 K (interminiband: 50 K). Cylindrical micro-cavities show single-mode behavior with a side mode suppression ratio better than 25 dB for both kinds of lasers.