This paper discusses the concept of enhancing semiconductor laser performance through tailoring of scattering rates of confined polar-optical phonons. Studies of optically pumped intersubband scattering in coupled quantum-well lasers have demonstrated that interface-phonon-assisted transitions are important in such structures; furthermore, simple analytical expressions have been derived that in...

In long wavelength quantum well lasers the effective electron temperature (T(e)) is often a strong function of the pump current and hence the T(e) correlates with the carrier concentration n in the active region. On the other hand, the material gain g in the active layer depends on both variables, g=g(n,T(e) ). We discuss a convenient way of analyzing this situation, based on considering the co...

In the framework of a microscopic model for intersubband gain from electrically pumped quantum-dot structures we investigate electrically pumped quantum-dots as active material for a mid-infrared quantum cascade laser. Our previous calculations have indicated that these structures could operate with reduced threshold current densities while also achieving a modal gain comparable to that of quan...

We demonstrate that a short hollow dielectric tube can act as a dielectric waveguide and transform the multimode, highly diverging terahertz quantum cascade laser beam into the lowest order dielectric waveguide hybrid mode, EH(11), which then couples efficiently to the free-space Gaussian mode, TEM(00). This simple approach should enable terahertz quantum cascade lasers to be employed in applic...

Static properties, relatively intensity noise and intensity modulation response in quantum cascade lasers (QCLs) studied theoretically in this paper. The present rate equations model consists of three equations for the electrons density in the conduction band and one equation for photons density in cavity length. Two equations were derived to calculate the noise and modulation response. Calcula...

The possibility of using the self-induced transparency effect to achieve laser mode locking has been discussed since the late 1960s but has never been observed. In prior work, we proposed that quantum cascade lasers are the ideal tool to realize self-induced transparency mode locking due to their rapid gain recovery times and relatively long coherence times, and because it is possible to interl...

In this work, we present the development of low consumption quantum cascade lasers across the mid-IR range. In particular, short cavity single-mode lasers with optimised facet reflectivities have been fabricated from 4.5 to 9.2 μm. Threshold dissipated powers as low as 0.5 W were obtained in continuous wave operation at room temperature. In addition, the beneficial impact of reducing chip lengt...

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