Article

Gain competition in dual wavelength quantum cascade lasers

School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Optics Express (Impact Factor: 3.53). 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

1 Follower
 · 
137 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: We report mass-producible room-temperature electrically-pumped THz sources based on intra-cavity difference-frequency generation in mid-infrared InGaAs/AlInAs/InP quantum cascade lasers. Devices are grown by a commercial foundry using metal organic vapor phase epitaxy. A dual-stack active region possessing giant optical nonlinearity for 3.5 THz generation and a non-collinear Cherenkov waveguide THz outcoupling scheme is employed. Fabry–Pérot devices provided broad emission in the 3–4 THz range with a peak power of 5 $mu{rm W}$. Single color THz sources were processed using surface distributed feedback gratings to produce narrowband $({
    IEEE Photonics Technology Letters 02/2014; 26(4):391-394. DOI:10.1109/LPT.2013.2294941 · 2.18 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We demonstrate 1.1W peak power at room-temperature from a double-waveguide quantum cascade laser (QCL) grown by metal-organic chemical vapor deposition. Two full broadband QCL active regions were grown on top of each other separated by thick cladding layers to reduce gain competition. Simultaneous lasing on Fabry-Perot modes separated by as much as 360 cm(-1) is obtained. This design paves the way for high-brightness broadband mid-infrared sources, as well as more complex three-terminal devices. (C) 2012 American Institute of Physics. [doi:10.1063/1.3678033]
    Applied Physics Letters 01/2012; 100(3):033502. DOI:10.1063/1.3678033 · 3.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Based on a four-level rate equations model, we carry out a detailed analysis of the two modes of a mid-infrared quantum cascade laser operating simultaneously on two laser lines having a common upper level. Analytical solutions are obtained for the steady-states and the stability analysis of these predicts that, depending on the injected current, the device lases on either one of the two modes or on both wavelengths simultaneously. We also show through numerical simulations that the injected current influences significantly the population inversions and photon numbers dynamics trajectory of a two mode laser where the higher the current the shorter the time needed to reach saturation and therefore steady state operation.
    Optics Communications 09/2013; 305:147–154. DOI:10.1016/j.optcom.2013.05.004 · 1.54 Impact Factor