Abstract:
Semiconductor lasers comprise a substrate; an active layer configured to generate transverse magnetic (TM) polarized light under an electrical bias; an upper cladding layer; a lower cladding layer; and a distributed feedback (DFB) grating defined by the interface of a layer of metal and a layer of semiconductor under the layer of metal, the interface periodically corrugated in the longitudinal direction of the laser with a periodicity of ΛDFB=mλ/(2neff), wherein m>1. The DFB grating is configured such that loss of one or more antisymmetric longitudinal modes of the laser structure via absorption to the DFB grating is sufficiently maximized so as to produce lasing of a symmetric longitudinal mode of the laser with laser emission characterized by a single-lobe beam along each direction defined by the grating diffraction orders corresponding to emission away from the plane of the grating.
Abstract:
Single-mode quantum cascade semiconductor lasers are provided. The lasers comprise a laser element, the laser element comprising a quantum cascade active layer; an upper cladding layer over the quantum cascade active layer; and a lower cladding layer under the quantum cascade active layer, wherein the quantum cascade active layer, the upper cladding layer and the lower cladding layer define a guided optical mode. The quantum cascade active layer and the upper and lower cladding layers are shaped in the form of a ridge structure having a front face, a back face opposite the front face, and a lasing face through which laser emission exits the ridge structure, the ridge structure configured such that the laser emission has a single-lobe, far-field beam pattern from the ridge structure comprising certain sections, including tapered sections, collateral sections, or both.
Abstract:
Methods for the fabrication of orientation-patterned semiconductor structures are provided. The structures are light-waveguiding structures for nonlinear frequency conversion. The structures are periodically poled semiconductor heterostructures comprising a series of material domains disposed in a periodically alternating arrangement along the optical propagation axis of the waveguide. The methods of fabricating the orientation-patterned structures utilize a series of surface planarization steps at intermediate stages of the heterostucture growth process to provide interlayer interfaces having extremely low roughnesses.
Abstract:
Methods for the fabrication of orientation-patterned semiconductor structures are provided. The structures are light-waveguiding structures for nonlinear frequency conversion. The structures are periodically poled semiconductor heterostructures comprising a series of material domains disposed in a periodically alternating arrangement along the optical propagation axis of the waveguide. The methods of fabricating the orientation-patterned structures utilize a series of surface planarization steps at intermediate stages of the heterostucture growth process to provide interlayer interfaces having extremely low roughnesses.
Abstract:
Virtual substrates made by hydride vapor phase epitaxy are provided comprising a semiconductor growth substrate and a substantially strain-relaxed metamorphic buffer layer (MBL) structure comprising one or more layers of a semiconductor alloy on the growth substrate. The MBL structure is compositionally graded such that its lattice constant transitions from a lattice constant at the interface with the growth substrate that is substantially the same as the lattice constant of the growth substrate to a lattice constant at a surface opposite the interface that is different from the lattice constant of the growth substrate. The virtual substrates comprise relatively thick MBL structures (e.g., >20 μm) and relatively thick growth substrates (e.g., >0.5 mm).
Abstract:
Virtual substrates made by hydride vapor phase epitaxy are provided comprising a semiconductor growth substrate and a substantially strain-relaxed metamorphic buffer layer (MBL) structure comprising one or more layers of a semiconductor alloy on the growth substrate. The MBL structure is compositionally graded such that its lattice constant transitions from a lattice constant at the interface with the growth substrate that is substantially the same as the lattice constant of the growth substrate to a lattice constant at a surface opposite the interface that is different from the lattice constant of the growth substrate. The virtual substrates comprise relatively thick MBL structures (e.g., >20 μm) and relatively thick growth substrates (e.g., >0.5 mm)
Abstract:
Semiconductor lasers comprise a substrate; an active layer configured to generate transverse magnetic (TM) polarized light under an electrical bias; an upper cladding layer; a lower cladding layer; and a distributed feedback (DFB) grating defined by the interface of a layer of metal and a layer of semiconductor under the layer of metal, the interface periodically corrugated in the longitudinal direction of the laser with a periodicity of ΛDFB=mλ/(2neff), wherein m>1. The DFB grating is configured such that loss of one or more antisymmetric longitudinal modes of the laser structure via absorption to the DFB grating is sufficiently maximized so as to produce lasing of a symmetric longitudinal mode of the laser with laser emission characterized by a single-lobe beam along each direction defined by the grating diffraction orders corresponding to emission away from the plane of the grating.