Abstract: A photovoltaic device is provided which includes a plurality of junction layers. Each junction layer includes a plurality of photovoltaic cells electrically connected to one another. At least one of the junction layers is at least in part optically transmissive. The junction layers are arranged in a stack on top of each other.

Abstract: A method is provided for producing a thin-film photovoltaic device. The method includes forming on a substrate a first thin-film absorber layer using a first deposition process. A second thin-film absorber layer is formed on the first thin-film absorber layer using a second deposition process different from the first deposition process. The first and second thin-film absorber layers are each photovoltaically active regions and the second thin-film absorber layer has a smaller concentration of defects than the first thin-film absorber layer.

Abstract: A method and apparatus of forming compositionally homogeneous particles is provided. The method includes forming a homogenous melt from a plurality of constituent materials under a first pressure sufficient to prevent substantial vaporization of the constituent materials. Droplets are generated from the homogenous melt. The droplets are cooled under a second pressure sufficient to prevent substantial vaporization of the constituent materials at least until the homogeneous particles formed therefrom have stabilized.

Abstract: A method is provided for producing a thin-film device such as a photovoltaic device. The method begins by forming at least one semiconductor device on a first substrate. At least one secondary substrate having a plurality of indentations is attached to the at least one semiconductor device. The at least one semiconductor device is separated from the at least one first substrate.

Abstract: A multi-input electrical power conversion device is provided for converting multiple DC energies each arising from different junctions in a multi-junction solar cells into AC energy. The device includes a plurality of electrical inputs for receiving the multiple DC energies from at least one multi junction solar cell. The number of DC energies id no less than the number of junctions in the multi-junction solar cell. The device also includes at least one DC-to-AC circuit for receiving the multiple DC energies from the plurality of electrical inputs and at least one electrical output receiving at least one AC energy from the DC to AC circuit. The device also includes at least one MPPT circuit operatively coupled to the DC to AC circuit.

Abstract: A photovoltaic device includes a plurality of photovoltaic cells disposed in an array in which each cell is adjacent to another cell. Each of the cells includes first and second photovoltaic modules. The first photovoltaic module of each cell is configured to convert a first part of light energy incident thereon into electrical energy and to reflect to the second photovoltaic module of an adjacent cell at least some of a remaining portion of light energy incident thereon. The second photovoltaic module of each cell is configured to convert into electrical energy the remaining portion of the light energy received from the first photovoltaic module of an adjacent cell.

Abstract: A method is provided for fabricating a thin film semiconductor device. The method includes providing a plurality of raw semiconductor materials. The raw semiconductor materials undergo a pre-reacting process to form a homogeneous compound semiconductor target material. The compound semiconductor target material is deposited onto a substrate to form a thin film having a composition substantially the same as a composition of the compound semiconductor target material.

Abstract: A method is provided for converting optical energy to electrical energy in a spectrally adaptive manner. The method begins by directing optical energy into a first photovoltaic module that includes non-single crystalline semiconductor layers defining a junction such that a first spectral portion of the optical energy is converted into a first quantity of electrical energy. A second spectral portion of the optical energy unabsorbed by the first module is absorbed by a second photovoltaic module that includes non-single crystalline semiconductor layers defining a junction and converted into a second quantity of electrical energy. The first quantity of electrical energy is conducted from the first module to a first external electrical circuit along a first path. The second quantity of electrical energy is conducted from the second module to a second external electrical circuit along a second path that is in parallel with the first path.

Abstract: An optical module is provided for performing a prescribed function such as dispersion compensation, for example. The optical module is to be integrated between stages of a multi-stage rare-earth doped optical amplifier. The module includes an input port for receiving optical energy from one stage of the rare-earth doped optical amplifier and a rare-earth doped planar waveguide coupled to the input port. An optically lossy, passive element is provided for performing the prescribed function. The optically lossy, passive element is coupled to the planar waveguide for receiving optical energy therefrom. An output port is coupled to the optically lossy, passive element for providing optical energy to another stage of the rare-earth doped optical amplifier.

Abstract: A multistage optical amplifier includes a fiber amplifier stage having an active optical fiber for imparting gain to an optical signal propagating therethrough and a coupler supplying pump energy to the optical fiber. A planar waveguide amplifier stage is optically coupled to the fiber amplifier stage. The waveguide amplifier including a substrate, an active planar waveguide formed on the substrate for imparting gain to an optical signal propagating therethrough, and at least one waveguide coupler formed on the substrate for coupling pump power to the active planar waveguide.

Abstract: A multistage optical amplifier includes a fiber amplifier stage having an active optical fiber for imparting gain to an optical signal propagating therethrough and a coupler supplying pump energy to the optical fiber. A planar waveguide amplifier stage is optically coupled to the fiber amplifier stage. The waveguide amplifier including a substrate, an active planar waveguide formed on the substrate for imparting gain to an optical signal propagating therethrough, and at least one waveguide coupler formed on the substrate for coupling pump power to the active planar waveguide.

Abstract: An optical device that is a waveguide with a heating element thereon that is formed on a silicon substrate is disclosed. The waveguide is formed on a region of porous silicon formed in the silicon substrate. The porous silicon region provides greater resistance to the flow of heat than the silicon substrate on which the device is formed. Optionally, the porous silicon region also provides greater resistance to the flow of heat than the waveguide.

Abstract: A process for fabricating a silica-based optical device on a silicon substrate is disclosed. The device has a cladding formed in a silicon substrate. The device also has an active region, and that active region is formed on the cladding. The cladding is fabricated by forming a region of porous silicon in the silicon substrate. The porous silicon is then oxidized and densified. After densification, the active region of the device is formed on the cladding.

Abstract: Optical devices using non-centric crystals, such as lithium niobate, and methods for making and using the devices, are provided. The devices provide improved temperature stability as compared to conventional devices using non-centric crystals. The improved temperature stability is provided by etching the surface of a non-centric crystal to a depth of less than about 300 angstroms. The devices and methods of the invention reduce the magnitude of change in bias voltage required to maintain an optical crystal at a pre-selected operating point.

Abstract: An improved waveguide optical amplifier having an optically transparent first cladding layer, an optically transparent film doped with an optically active material, disposed over the first cladding layer, at least one undoped optically transparent film disposed over the doped film and coating etched walls of the doped film, and an optically transparent second cladding layer disposed over the undoped film. At least a portion of the undoped film disposed immediately adjacent the doped film has an index of refraction which is closer to the index of refraction of the doped film, than to the index of refraction of the second cladding layer and preferably equal thereto. The undoped film covers surface imperfections in the etched walls of the doped film, effectively moving them from the doped film/undoped film interface to the undoped film/cladding layer interface thereby reducing scattering of the high-intensity mode field.