Abstract: An epitaxial material grown laterally in a trench allows for the fabrication of a trench-based semiconductor material that is substantially low in dislocation density. Initiating the growth from a sidewall of a trench minimizes the density of dislocations present in the lattice growth template, which minimizes the dislocation density in the regrown material. Also, by allowing the regrowth to fill and overflow the trench, the low dislocation density material can cover the entire surface of the substrate upon which the low dislocation density material is grown. Furthermore, with successive iterations of the trench growth procedure, higher quality material can be obtained. Devices that require a stable, high quality epitaxial material can then be fabricated from the low dislocation density material.

Abstract: A light emitting device and photodetector combination having a structure in which the layer of the photodetector that contacts the light emitting device is separated from the light emitting device by a native semiconductor oxide layer that is both insulating and has a refractive index lower than that of the light emitting device and the photodetector. This configuration results in a light emitting device and photodetector structure that minimizes the capture of the spontaneous emission light output from the light emitting device by the photodetector while electrically isolating the light emitting device from the photodetector. The electrical isolation of the light emitting device from the photodetector results in a four terminal device in which the light emitting device and photodetector may be independently biased, and can therefore be operated at a very low bias voltage.

Abstract: A vertical cavity surface-emitting laser, and method of fabricating such a laser, for use in an optical communication system including an optical cavity arranged between a pair of distributed Bragg reflectors, an active region in the optical cavity, and an oxidized current confinement layer arranged on one side of the active layer. The current confinement layer includes a component, such as antimony, that is segregated into a conductive layer on one side of the current confinement layer during oxidation.

Abstract: An optical semiconductor device having an active layer for generating light via the recombination of holes and electrons therein. The active layer is part of a plurality of semiconductor layers including an n-p junction between an n-type layer and a p-type layer. The active layer has a polarization field therein having a field direction that depends on the orientation of the active layer when the active layer is grown. In the present invention, the polarization field in the active layer has an orientation such that the polarization field is directed from the n-layer to the p-layer.

Abstract: A method for growing a crystalline layer that includes a first material on a growth surface of a crystalline substrate of a second material, wherein the first material and the second material have different lattice constants. A buried layer is generated in the substrate such that the buried layer isolates a layer of the substrate that includes the growth surface from the remainder of the substrate. The second material is then deposited on the growth surface at a growth temperature. The isolated layer of the substrate has a thickness that is less than the thickness at which defects are caused in the crystalline lattice of the first material by the second material crystallizing thereon. The buried layer is sufficiently malleable at the growth temperature to allow the deformation of the lattice of the isolated layer without deforming the remainder of the substrate. The present invention may be utilized for growing III-V semiconducting material layers on silicon substrates.

Abstract: An optical element having a variable index of refraction. The optical element utilizes a layer of a transparent dielectric material having an index of refraction determined by the concentration of hydrogen in the dielectric material. A layer of a hydrogen reservoir medium that includes a material that acts as a source or a sink for hydrogen is placed adjacent to the transparent dielectric layer. The reservoir medium accepts hydrogen from the transparent layer in response to a first electric field being applied across the transparent layer and reservoir layer and donates hydrogen to the transparent layer in response to a second electric field being applied across the transparent layer and the reservoir layer. The electric fields are generated by applying appropriate potentials across first and second electrodes that sandwich the dielectric and reservoir layers. The preferred reservoir material is KOH.

Abstract: A method for growing a crystalline layer that includes a first material on a growth surface of a crystalline substrate of a second material, wherein the first material and the second material have different lattice constants. A buried layer is generated in the substrate such that the buried layer isolates a layer of the substrate that includes the growth surface from the remainder of the substrate. The second material is then deposited on the growth surface at a growth temperature. The isolated layer of the substrate has a thickness that is less than the thickness at which defects are caused in the crystalline lattice of the first material by the second material crystallizing thereon. The buried layer is sufficiently malleable at the growth temperature to allow the deformation of the lattice of the isolated layer without deforming the remainder of the substrate. The present invention may be utilized for growing III-V semiconducting material layers on silicon substrates.

Abstract: An optically pumped vertical-cavity surface-emitting laser (VCSEL) device and a method of fabricating the device utilize two separate substrates that perform a filtering operation to selectively transmit only light having a long peak wavelength that is generated by the device. The optically pumped VCSEL device is a self-pumped device that can generate the pump light to drive the device to emit output laser light having a long peak wavelength. The optically pumped VCSEL device includes a short-wavelength VCSEL formed on one of the two substrates and a long-wavelength VCSEL formed on the other substrate. The short-wavelength VCSEL is a current-driven VCSEL that generates short-wavelength light to drive (i.e., optically pump) the long-wavelength VCSEL. The short-wavelength VCSEL and the long-wavelength VCSEL are bonded together such that the two substrates are separated by the two VCSELs.

Abstract: A light emitting device and photodetector combination having a structure where the layer of the photodetector that contacts the light emitting device has a semiconductor conductivity type polarity opposite that of the light emitting device. This configuration results in a light emitting device and photodetector structure that has a very low bias voltage requirement. Additionally, by shunting any current flowing through the junction formed where the light emitting device meets the photodetector, the bias voltage requirement is further reduced.

Abstract: A method for growing a crystalline layer that includes a first material on a growth surface of a crystalline substrate of a second material, wherein the first material and the second material have different lattice constants. A buried layer is generated in the substrate such that the buried layer isolates a layer of the substrate that includes the growth surface from the remainder of the substrate. The first material is then deposited on the growth surface at a growth temperature. The isolated layer of the substrate has a thickness that is less than the thickness at which defects are caused in the crystalline lattice of the second material by the first material crystallizing thereon. The buried layer is sufficiently malleable at the growth temperature to allow the deformation of the lattice of the isolated layer without deforming the remainder of the substrate. The present invention may be utilized for growing III-V semiconducting material layers on silicon substrates.

Abstract: A Vertical Cavity Surface-Emitting Laser (VCSEL) assembly in which the polarization is locked to a specified direction that is the same for all VCSELs. A VCSEL according to the present invention includes a VCSEL having a top mirror region, a bottom mirror region, a light generation region between the top and bottom mirror regions, a conducting substrate and a bottom electrode. The bottom mirror region is sandwiched between the conducting substrate and the light generation region, and the conducting substrate is sandwiched between the bottom electrode and the bottom mirror region. The assembly also includes a mounting substrate having top and bottom surfaces, the VCSEL being mechanically coupled to the mounting substrate. The mounting substrate includes a means for defining a first axis. The assembly includes a means for causing the mounting substrate to flex about the first axis thereby inducing a strain in the light generation region which locks the polarization into a mode determined by the first axis.

Abstract: A buried reflector 50 in an epitaxial lateral growth layer forms a part of a light emitting device and allows for the fabrication of a semiconductor material that is substantially low in dislocation density. The laterally grown material is low in dislocation defect density where it is grown over the buried reflector making it suitable for high quality optical light emitting devices, and the embedded reflector eliminates the need for developing an additional reflector.

Abstract: A VCSEL with a near planar top surface on which the top electrode is deposited. A VCSEL according to the present invention includes a top electrode, a top mirror having a top surface, a light generation region, and a bottom mirror for reflecting light toward the top mirror. At least one of the mirrors includes a plurality of planar electrically conducting layers having different indices of refraction. In addition, at least one of the layers includes an oxidizable material. To expose this layer to an oxidizing agent (thereby converting the material to an electrical insulator), three or more holes are etched down from the top surface of the VCSEL to the layer containing the oxidizable material. The oxidizing agent is then introduced into the top of these holes. The partial oxidation of the layer converts the layer to one having a conducting region surrounded by an electrically insulating region, the conducting region being positioned under the top electrode.

Abstract: A VCSEL that laser comprises a first mirror layer, an active layer including a quantum well region and a diffusion enhancing region, and a second mirror layer. The first and second mirror layers are layers of doped semiconductor material having a first and a second conductivity mode, respectively. The active layer is a layer of semiconductor material adjacent the first mirror layer. The second mirror layer is adjacent the active layer, remote from the first mirror layer. The diffusion enhancing region is a region of the active layer in which the semiconductor material of the active layer is doped with an acceptor impurity to such a high concentration that holes induced in the quantum well region by the diffusion enhancing region predominate over electrons in the quantum well region by about one order of magnitude.

Abstract: A VCSEL 101 comprising an optical cavity having an optical loss and a loss-determining element 117 coupled to the optical cavity. The loss-determining element 117 progressively increases the optical loss of the optical cavity with increasing lateral distance from the optical axis 105. The optical cavity includes a first mirror region 111, a second mirror region 107, a plane light-generating region 125 sandwiched between the first mirror region 111 and the second mirror region 107, perpendicular to the optical axis 105, and an element 113 that defines the lateral extent of the optical cavity in the plane of the light-generating region 125. The first mirror region 111 and the second mirror region 107 are both conductive and have opposite conductivity modes.

Abstract: An integrated laser-based light source that generates an output light beam having a controlled intensity. The light source comprises a package, a laser, a light sensor, and a beam splitter. The beam splitter is mounted in the package, together with the laser and the light sensor. The laser has one and only one light-emitting face from which it radiates a light beam as a radiated light beam. The light sensor generates an electrical signal representing the intensity of light energy falling on it. The beam splitter divides the radiated light beam into a fraction and a remainder, the remainder being the output light beam. The beam splitter operates by diffraction, scattering, or transmission to direct the fraction of the radiated light beam towards the light sensor.

Abstract: An integrated laser-based light source that generates an output light beam having a controlled intensity. The light source comprises a package in which are mounted a laser, a light sensor and a coupler. The laser has one and only one light-emitting face from which a light beam is radiated as a radiated light beam. The light sensor generates an electrical signal representing the intensity of light energy falling it. The coupler couples a fraction of the radiated light beam to the light sensor, and provides the remainder of the radiated light beam as the output light beam. Since the light coupled to the light sensor by the coupler is a fraction of the radiated light beam, the electrical signal generated by the light sensor also represents the intensities of the radiated light beam and of the output light beam.

Abstract: An integrated laser-based light source that generates an output light beam having a controlled intensity. The light source comprises a package in which are mounted a laser, a light sensor and a coupler. The laser has one and only one light-emitting face from which a light beam is radiated as a radiated light beam. The light sensor generates an electrical signal representing the intensity of light energy falling it. The coupler couples a fraction of the radiated light beam to the light sensor, and provides the remainder of the radiated light beam as the output light beam. Since the light coupled to the light sensor by the coupler is a fraction of the radiated light beam, the electrical signal generated by the light sensor also represents the intensities of the radiated light beam and of the output light beam.

Abstract: A vertical-cavity surface-emitting laser that generates light having a fixed direction of polarization. The laser has a plane light-generating region sandwiched between a first conductive mirror region and a second conductive mirror region. The first conductive mirror region has an opposite conductivity mode from the second conductive mirror region. The first conductive mirror region has a remote surface substantially parallel to the light-generating region and an electrode formed on the remote surface. The electrode bounds a light emission port from which the light is emitted in a direction defining an axis. A reduced-conductivity region is formed in the first conductive mirror region surrounding the axis and extending from the remote surface towards the light-emitting region to define a core region in the first conductive mirror region. The light emission port and/or the core region has first and second dimensions in orthogonal directions in a plane parallel to the light-generating region.