Gain competition in dual wavelength quantum cascade lasers

School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Optics Express (Impact Factor: 3.49). 05/2010; 18(10):9900-8. DOI: 10.1364/OE.18.009900
Source: PubMed

ABSTRACT We investigated dual wavelength mid-infrared quantum cascade lasers based on heterogeneous cascades. We found that due to gain competition laser action tends to start in higher order lateral modes. The mid-infrared mode with the lower threshold current reduces population inversion for the second laser with the higher threshold current due to stimulated emission. We developed a rate equation model to quantitatively describe mode interactions due to mutual gain depletion. (C) 2010 Optical Society of America

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