Patent ID: 9077153
Filing Date: 2015-07-07
Classification: H01S

Abstract:
1. An improved quantum cascade laser, the improvement comprising a non-uniform dielectric waveguide, the dielectric waveguide comprising: (a) a longitudinally straight section having a first end, a second end, a ridge width, and a length; and (b) a longitudinally tapered section at the second end of the straight section, the tapered section having a first end and a second end, the first end of the tapered section being connected to the second end of the straight section, the tapered section having a length, the tapered section tapering at a taper angle from a facet width of the tapered section at the second end of the tapered section to the ridge width at the first end of the tapered section, the taper angle being less than a delineation angle of the dielectric waveguide; and (c) wherein the delineation angle being given by the equation: where w and t are the width and a thickness of the dielectric waveguide, respectively, λ is a radiation wavelength, n core is a core refractive index, n clad is a cladding refractive index, and n eff is an effective refractive index of a waveguide mode.