Abstract:
One embodiments includes a method that includes enabling an excitation laser during an excitation period, after a timed delay following the first excitation period, monitoring a photon scattering caused by the excitation laser, analyzing the photon scattering, automatically adjusting the timed delay to a modified timed delay based on the analyzed photon scattering and following the modified timed delay, enabling a Raman spectrometer to monitor Raman scattering caused by the excitation laser during a Raman monitoring period.
Abstract:
A vertical cavity surface emitting laser (VCSEL) includes independently definable current and optical confinement structures that provide unique forms of drive current and transverse mode confinement, respectively. The optical guide may be formed from an upper distributed Bragg reflector (DBR), as an etched mesa structure and/or as an intracavity optical guide. The current guide may include an ion-implanted region within the upper DBR. A dielectric structure is formed over the upper DBR and surrounds the optical guide.
Abstract:
A pressure sensor includes a housing portion with a fluid inlet and a polymer element within the housing portion. The polymer element may be coated with piezoresistive material to form a first resistor and may have associated electrodes. The polymer element includes a first resistance value that changes to a second resistive value in a response to a predetermined condition. The pressure sensor may also include a second polymer element that includes a first resistance value that changes to a second resistive value in a response to a predetermined condition.
Abstract:
A long wavelength vertical cavity surface emitting laser having a substrate, a first mirror situated on the substrate, an active region situated on the first mirror, a second mirror situated on the active region. The first mirror may have several pairs of layers with an oxidized layer in one or more pairs of that mirror. The substrate may include InP and the mirror components may be compatible with the InP. The one or more layers in the first mirror may be oxidized via a trench-like approach or other arrangement.
Abstract:
A control system coupled to a pressure sensor calibrates the pressure sensor. The control system may measure a plurality of capacitance values at a plurality of corresponding applied voltages to compare the values with a first calibration mechanism generated by sample pressure sensors in a comparison. A final calibration mechanism may be generated by adjusting the first calibration mechanism in response to the comparison. The unknown differential pressure may be applied to a diaphragm of the pressure sensor. A capacitance value at the unknown differential pressure may then be measured. Using the final calibration mechanism, the differential pressure at the measured capacitance value may be retrieved.
Abstract:
A valve is provided that can selectively change the size of a flow channel in a valve in order to modulate the fluid flow through the valve. In one illustrative embodiment, the valve includes a housing that defines a cavity, with an inlet and an outlet extending into the cavity. A diaphragm is positioned in the cavity, where at least part of the diaphragm defines at least part of the fluid path. One or more electrodes are fixed relative to the diaphragm, and one or more electrodes are fixed relative to the housing such that the diaphragm can be electrostatically actuated to modulate the fluid flow through the valve.
Abstract:
A valve for regulating the flow of fluids (gas or liquid) using two flexible diaphragms in which an additional element is added to promote rolling contact between the diaphragms. The valve operates in a normally open configuration where fluid flows into the valve, passed through holes or openings in two electrostatically operative diaphragms and out of the valve. The holes or openings in one diaphragm are offset from the holes or openings in the other diaphragm, so that upon electro-static actuation, the diaphragms will seal together, closing the valve.
Abstract:
A VCSEL includes a substrate having a partially removed portion; a metal-assisted DBR having a metal layer and a first mirror stack, wherein the metal layer is located at the partially removed portion of the substrate; an active region having a plurality of quantum wells over the metal-assisted DBR; and a second mirror stack over the active region, wherein a number of alternating layers of the first mirror stack is substantially smaller than a number typically required for a VCSEL without the integrated metal reflector. Such a metal-assisted DBR is especially useful for a long-wavelength VCSEL on a InP substrate or a red-color VCSEL on a GaAs substrate.
Abstract:
A vertical cavity surface emitting laser (VCSEL) structure includes a bottom distributed Bragg reflector (DBR) arranged over a substrate; a metal layer interposed between the bottom DBR and the substrate, wherein the metal layer and bottom DBR form a composite mirror structure. A patterned dielectric layer may be interposed between the metal layer and the bottom DBR to reduce a deleterious chemical reaction between the metal layer and the bottom DBR. The metal layer directly contacts a portion of the bottom DBR to enhance the electrical and thermal conductivity of the
Abstract:
A device for sensing pressure including a chamber defining part having a first diaphragm mounted in communication with the sealed chamber defining part, and a second diaphragm electrically insulated from the first, preferably by a spacer. The diaphragms are flexible and have a conductive surface. A sensor chamber is mounted on the other side of the second diaphragm. It has an opening in communication with a sensing atmosphere. One of the diaphragms includes openings it its surface to permit fluid to flow through the openings and the other diaphragm is solid and responds to change in pressure in the sensor chamber to move away from or toward the one diaphragm. Electrical connections measure the capacitance between the diaphragms as a function of the pressure in the sensor chamber.