Tapered-Waveguide High-Power Quantum Cascade Lasers

摘要

An improved quantum cascade laser, the improvement comprising a longitudinally non-uniform dielectric waveguide. The waveguide includes a longitudinally straight section and a longitudinally tapered section. The length of the tapered section is between 5% and 50% of the total cavity length. The tapered section tapers at a taper angle from the facet width to the ridge width. The taper angle is smaller than the delineation angle of the waveguide.

主权项

1. An improved InP-based, buried-heterostructure quantum cascade laser emitting at 4.7 μm, the improvement comprising a longitudinally non-uniform dielectric waveguide having a total cavity length of 10 mm, the dielectric waveguide comprising:
(a) a longitudinally straight section having a first end, a second end, a ridge width, and a length, the ridge width being 7.5 μm, and the length being 9 mm; (b) a first tapered section at the first end of the straight section, the first tapered section having a first end and a second end, the second end of the first tapered section being connected to the first end of the straight section, the first tapered section having a length, the length of the first tapered section being 0.5 mm, the first tapered section tapering at a taper angle from a facet width of the first tapered section at the first end of the first tapered section to the ridge width at the second end of the first tapered section, the facet width of the first tapered section being 20 μm and the taper angle of the first tapered section being 0.7 degrees; and (c) a second tapered section at the second end of the straight section, the second tapered section having a first end and a second end, the first end of the second tapered section being connected to the second end of the straight section, the second tapered section having a length, the length of the second tapered section being 0.5 mm, the second tapered section tapering at a taper angle from a facet width of the second tapered section at the second end of the second tapered section to the ridge width at the first end of the second tapered section, the facet width of the second tapered section being 20 μm and the taper angle of the second tapered section being 0.7 degrees.