%0 Journal Article %J APPLIED PHYSICS LETTERS %D 2014 %T Mode switching in a multi-wavelength distributed feedback quantum cascade laser using an external micro-cavity %A Sidler, Meinrad %A Rauter, Patrick %A Blanchard, Romain %A Metivier, Pauline %A Mansuripur, Tobias S. %A Wang, Christine %A Huang, Yong %A Ryou, Jae-Hyun %A Dupuis, Russell D. %A Faist, Jerome %A Federico Capasso %X We demonstrate a multi-wavelength distributed feedback (DFB) quantum cascade laser (QCL) operating in a lensless external micro-cavity and achieve switchable single-mode emission at three distinct wavelengths selected by the DFB grating, each with a side-mode suppression ratio larger than 30 dB. Discrete wavelength tuning is achieved by modulating the feedback experienced by each mode of the multi-wavelength DFB QCL, resulting from a variation of the external cavity length. This method also provides a post-fabrication control of the lasing modes to correct for fabrication inhomogeneities, in particular, related to the cleaved facets position. (C) 2014 AIP Publishing LLC. %B APPLIED PHYSICS LETTERS %I AMER INST PHYSICS %C CIRCULATION & FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA %V 104 %P 051102 %8 FEB 3 %G eng %U https://doi.org/10.1063/1.4863663 %N 5 %9 Article %R 10.1063/1.4863663