摘要:
Disclosed is a graded index separate confinement heterostructure quantum well (GRIN-SCH QW) laser with continuously graded, substantially index matched InGaAsP confinement layer. The inventive device is well adapted for high power output in the wavelength region 1.2-1.68 .mu.m. In particular, it can readily be designed to have an output wavelength that makes it suitable as pump source for Er-doped optical fiber amplifiers. A method of manufacturing a laser according to the invention is also disclosed.
摘要:
When high-vacuum methods are used in the manufacture of miniaturized devices such as, e.g., semiconductor integrated-circuit devices, device layers on a substrate are preferably patterned without breaking of the vacuum. Preferred patterning involves deposition of a semiconductor mask layer, generation of the pattern in the mask layer by ion deflected-beam writing, and transfer of the pattern by dry etching. When the mask layer is an epitaxial layer, further epitaxial layer deposition after patterning may proceed without removal of remaining mask layer material.
摘要:
A strained layer superlattice comprising Ge.sub.x Si.sub.1-x layers interleaved with Si layers is an excellent photodetector at infrared wavelengths due to the large shift in bandgap caused by the strain in the superlattice.
摘要:
A buried-heterostructure distributed feedback laser is described, including a grating structure at a surface of a nonplanar cladding layer. The grating structure can be made by transfer of a pattern by ion milling, the pattern being defined in an ion-beam resist layer, e.g., by direct-writing electron-beam exposure. Low-threshold, high-power lasers are obtained with a commercially favorable yield.
摘要:
Several methods are used in novel ways with newly identified and viable parameters to decrease the peak transition energies of the pseudomorphic InGaAs/GaAs heterostructures. These techniques, taken separately or in combination, suffice to permit operation of light emitting devices at wavelengths of 1.3 μm or greater of light-emitting electro-optic devices. These methods or techniques, by example, include: (1) utilizing new superlattice structures having high In concentrations in the active region, (2) utilizing strain compensation to increase the usable layer thickness for quantum wells with appropriately high In concentrations, (3) utilizing appropriately small amounts of nitrogen (N) in the pseudomorphic InGaAsN/GaAs laser structure, and (4) use of nominal (111) oriented substrates to increase the usable layer thickness for quantum wells with appropriately high In concentrations. In all of the above techniques, gain offset may be utilized in VCSELs to detune the emission energy lower than the peak transition energy, by about 25 meV or even more, via appropriate DBR spacing. Gain offset may also be utilized in some forms of in-plane lasers. Increased temperature may also be used to decrease peak transition energy (and therefore the emission energy) by about 50 meV/100° C. All these techniques are furthermore applicable to other material systems, for example, extending the emission wavelength for laser diodes grown on InP substrates. Additionally, structures which utilize the above techniques are discussed.
摘要:
An optical waveguide mode transformer has a substrate supporting a high refractive index core layer surrounded by lower refractive index cladding. The core layer includes a wide input waveguide section to accept a multimode, including a fundamental mode, light input. The input waveguide section is coupled to a narrow output waveguide section by a tapered region having a taper length enabling adiabatic transfer of the fundamental mode of the multimode light from the wide input waveguide section to the output waveguide section while suppressing(stripping) other modes of the multimode light input. The narrow output waveguide section supports a single mode light output comprising said fundamental mode. The core layer is contoured to include a localized upstanding ridge intermediate opposite lateral sides of the core layer. The output waveguide section includes a portion having a real index step between the core layer and cladding layers, and advantageously is functional to output a light beam having similar vertical and horizontal divergences.
摘要:
An optical waveguide device comprising a free space region, suitably provided by a slab waveguide, having optical signal ports for coupling to input and output waveguide sections and an optical waveguide grating including an array of grating waveguides coupling the free space region to a reflector surface to provide a folded structure. Dielectric waveguide structures are preferred. The grating includes tapered optical waveguide sections laterally spaced and optically isolated from each other which extend from the free space region, with the grating waveguides continuing as extensions of the tapered waveguide sections. Each of the grating waveguides differs in length from a neighboring grating waveguide by a constant increment, preferably an optical path length increment. The grating waveguides also include intermediate curved portions having respective curvatures which increase progressively, preferably in an approximately parabolic manner, according to the sequential location of the grating waveguides from a reference grating waveguide in the array.
摘要:
Several methods are used in novel ways with newly identified and viable parameters to decrease the peak transition energies of the pseudomorphic InGaAs/GaAs heterostructures. These techniques, taken separately or in combination, suffice to permit operation of light emitting devices at wavelengths of 1.3 &mgr;m or greater of light-emitting electro-optic devices. These methods or techniques, by example, include: (1) utilizing new superlattice structures having high In concentrations in the active region, (2) utilizing strain compensation to increase the usable layer thickness for quantum wells with appropriately high In concentrations, (3) utilizing appropriately small amounts of nitrogen (N) in the pseudomorphic InGaAsN/GaAs laser structure, and (4) use of nominal (111) oriented substrates to increase the usable layer thickness for quantum wells with appropriately high In concentrations. In all of the above techniques, gain offset may be utilized in VCSELs to detune the emission energy lower than the peak transition energy, by about 25 meV or even more, via appropriate DBR spacing. Gain offset may also be utilized in some forms of in-plane lasers. Increased temperature may also be used to decrease peak transition energy (and therefore the emission energy) by about 50 meV/100° C. All these techniques are furthermore applicable to other material systems, for example, extending the emission wavelength for laser diodes grown on InP substrates. Additionally, structures which utilize the above techniques are discussed.
摘要:
Several methods are used in novel ways with newly identified and viable parameters to decrease the peak transition energies of the pseudomorphic InGaAs/GaAs heterostructures. These techniques, taken separately or in combination, suffice to permit operation of light emitting devices at wavelengths of 1.3 .mu.m or greater of light-emitting electro-optic devices. These methods or techniques, by example, include: (1) utilizing new superlattice structures having high In concentrations in the active region, (2) utilizing strain compensation to increase the usable layer thickness for quantum wells with appropriately high In concentrations, (3) utilizing appropriately small amounts of nitrogen (N) in the pseudomorphic InGaAsN/GaAs laser structure, and (4) use of nominal (111) oriented substrates to increase the usable layer thickness for quantum wells with appropriately high In concentrations. In all of the above techniques, gain offset may be utilized in VCSELs to detune the emission energy lower than the peak transition energy, by about 25 meV or even more, via appropriate DBR spacing. Gain offset may also be utilized in some forms of in-plane lasers. Increased temperature may also be used to decrease peak transition energy (and therefore the emission energy) by about 50 meV/100.degree. C. All these techniques are furthermore applicable to other material systems, for example, extending the emission wavelength for laser diodes grown on InP substrates. Additionally, structures which utilize the above techniques are discussed.
摘要:
Expedient fabrication of fine-featured integrated circuits entails aperture pattern delineation to produce a masking layer atop a semiconductor body followed by insertion within a controlled atmosphere chamber within which device-functional layered material is epitaxially grown within apertures. Critical, device-consequential properties of epitaxial material is assured by removal of a thin surface layer of material revealed during delineation. Such removal, sufficient to eliminate meaningful contamination and/or crystalline damage introduced during delineation, is of sufficiently small quantity as to be accommodated within the chamber. Under most circumstances, the controlled atmosphere is at reduced pressure as required for e.g. MOMBE epitaxial growth.