The possibility of realizing single-mode emission in quantum-cascade lasers due to modulation of output optical losses in a Fabry-Perot cavity is demonstrated. For the active region of the 7.5–8.0 μm spectral range, two-phonon resonance design we used thus the 50 stages and waveguide layers based on indium phosphide made it possible to realize single-mode lasing at 7.765 μm and at temperature of 292 K. Side-mode suppression ratio was about 24 dB and remained the same with an increase in the current pumping up to 1.2 of the threshold current values. The coefficient of wavelength shift with temperature (temperature tuning) in the single-mode lasing regime was 0.56 nm / K.
Erratum: “Single-mode quantum cascade lasers based on a folded Fabry–Perot cavity” [Appl. Phys. Lett. 98, 061110 (2011)]