Interband Cascade Photonic Integrated Circuits on Native III-V Chip

We describe how a midwave infrared photonic integrated circuit (PIC) that combines lasers, detectors, passive waveguides, and other optical elements may be constructed on the native GaSb substrate of an interband cascade laser (ICL) structure. The active and passive building blocks may be used, for example, to fabricate an on-chip chemical detection system with a passive sensing waveguide that evanescently couples to an ambient sample gas. A variety of highly compact architectures are described, some of which incorporate both the sensing waveguide and detector into a laser cavity defined by two high-reflectivity cleaved facets. We also describe an edge-emitting laser configuration that optimizes stability by minimizing parasitic feedback from external optical elements, and which can potentially operate with lower drive power than any mid-IR laser now available. While ICL-based PICs processed on GaSb serve to illustrate the various configurations, many of the proposed concepts apply equally to quantum-cascade-laser (QCL)-based PICs processed on InP, and PICs that integrate III-V lasers and detectors on silicon. With mature processing, it should become possible to mass-produce hundreds of individual PICs on the same chip which, when singulated, will realize chemical sensing by an extremely compact and inexpensive package.

Гетероструктуры квантово-каскадных лазеров с неселективным заращиванием методом газофазной эпитаксии

The possibility of fabrication of 4.6 µm spectral range quantum-cascade laser heterostructures by molecular-beam epitaxy technique with non-selective overgrowth by the metalorganic vapour-phase epitaxy is shown. The active region of the laser was formed on the basis of a heteropair of In0.67Ga0.33As/In0.36Al0.64As solid alloys. The waveguide claddings are formed by indium phosphide. The results of surface defects inspection and X-ray diffraction analysis of quantum-cascade laser heterostructures allow to conclude that the structural quality of the heterostructures is high and the estimated value of the root mean square surface roughness does not exceed 0.7 nm. Lasers with four cleaved facets exhibit lasing at room temperature with a relatively low threshold current density of the order of 1 kA /cm2.

Гетероструктуры квантово-каскадных лазеров спектрального диапазона 4.6 μm для реализации непрерывного режима генерации

An elastically balanced heterostructure of a 4.6-μm wavelength range quantum-cascade laser was grown by using molecular beam epitaxy. Heterostruсture was based on a heteropair of In0.67Ga0.33As / In0.36Al0.64As solid alloys and indium phosphide layers, which served as waveguide claddings. A high homogeneity of the layers composition and thicknesses in cascades over the wafer was proved by using X-ray diffraction for the grown heterostructure. Lasers with four cleaved facets operate at room temperature at a wavelength near 4.6 μm with a low threshold current density of 1.1 kA / cm2

Мощные квантово-каскадные лазеры с длиной волны генерации 8 μm

The heterostructure of a quantum-cascade laser based on In0.53Ga0.47As/Al0.48In0.52As heteropair lattice matched with the InP was grown by molecular beam epitaxy. InP layers was used to form the optical waveguide. Room temperature lasing in the spectral range of 8 μm in the standard ridge geometry of a Fabry-Perot cavity formed by cleaved facets with peak output optical power of 0.45 W was obtained.

Stimulated emission at 272 nm from an AlxGa1−xN-based multiple-quantum-well laser with two-step etched facets

We demonstrate an optically pumped AlGaN-based laser at 272 nm with two-step etched facets. Compared with a laser with cleaved facets, the laser with etched facets had a lower threshold and higher differential quantum efficiency.