Abstract: A system for measuring a target gas via laser absorption spectroscopy in an open-air configuration, comprising a mid-infrared distributed feedback interband cascade laser (mid-IR DFB-ICL) having a wavelength selected to correspond with a spectral absorption line of the target gas and first electronic circuitry to control the laser temperature, current and modulation frequency. The mid-IR DFB-ICL is mounted to a heat sink. The system includes an optical component that projects a beam of the mid-IR DFB-ICL onto a distal backscattering directionally-reflective target and an optical receiver assembly that receives a fraction of the laser light that is backscattered from the directionally-reflective target and focuses the collected light onto an uncooled photodetector having a spectral bandwidth and optical configuration selected to optimize signal-to-noise response to received laser light.

Abstract: Systems and method for analysing contaminants of a gas sample of natural gas are provided. An interrogation light beam propagates into a chamber of a multipass gas cell receiving the gas sample. The interrogation light beam has a wavelength controlled to alternately correspond to an absorption wavelength of H2S and an absorption wavelength of an additional gas contaminant. The additional gas contaminant may for example be CO2 or H2O. In some implementation, a single laser emitter may be used to generate the interrogation light beam at the H2S and CO2 wavelengths. In some implementations, two different laser emitters may be used to generate the interrogation light beam at the H2S and H2O wavelengths. A WMS detection scheme may be used.

Abstract: Systems and method for analysing contaminants of a gas sample of natural gas are provided. An interrogation light beam propagates into a chamber of a multipass gas cell receiving the gas sample. The interrogation light beam has a wavelength controlled to alternately correspond to an absorption wavelength of H2S and an absorption wavelength of an additional gas contaminant. The additional gas contaminant may for example be CO2 or H2O. In some implementation, a single laser emitter may be used to generate the interrogation light beam at the H2S and CO2 wavelengths. In some implementations, two different laser emitters may be used to generate the interrogation light beam at the H2S and H2O wavelengths. A WMS detection scheme may be used.

Abstract: An apparatus for detecting leaks from a gas pipeline or storage system includes a light source configured to emit a beam with at least one spectral component capable of interacting with pipeline gas, a reflector configured to reflect a portion of the beam, an optical detector configured to detect the reflected beam, a signal processing module coupled to the output of the optical detector configured to analyze the detected beam and output a measured concentration value that characterizes the amount of target gas in the beam path, and a statistical processing module coupled to the signal processing module configured to store and analyze the measured concentration value. The statistical processing module is further configured to compute a value based on statistical information associated with the stored plurality of concentration values and compare the computed value to a first predetermined threshold, and transmit a first alarm signal if the computed value is greater than the first predetermined threshold.

Abstract: An apparatus for detecting leaks from a gas pipeline or storage system includes a light source configured to emit a beam with at least one spectral component capable of interacting with pipeline gas, a reflector configured to reflect a portion of the beam, an optical detector configured to detect the reflected beam, a signal processing module coupled to the output of the optical detector configured to analyze the detected beam and output a measured concentration value that characterizes the amount of target gas in the beam path, and a statistical processing module coupled to the signal processing module configured to store and analyze the measured concentration value. The statistical processing module is further configured to compute a value based on statistical information associated with the stored plurality of concentration values and compare the computed value to a first predetermined threshold, and transmit a first alarm signal if the computed value is greater than the first predetermined threshold.

Abstract: A light scattering sensor is provided with a cylindrical lens focusing received light along substantially parallel lines, or bands, that correspond to a range of scattering angles and a linear detector that detects the light intensity along the substantially parallel lines. By using a cylindrical lens, the lens serves as an auto-collimator, whereby light scattered at a specific angle from the collimated light beam strikes the linear detector at a corresponding specific location regardless of the location from where the light was scattered. Embodiments of the cylindrical lens-based light sensor can be applied to a number of different applications and industries that analyze light scattering intensity as a function of scattering angle. For example, embodiments of the cylindrical lens-based light scattering sensor can be used for monitoring a target fluid for contaminants.

Abstract: A mode converter including a silicon waveguide core deposited over a first silicon dioxide cladding layer. The silicon waveguide core is formed such that a first end of the silicon waveguide core has a larger cross-sectional area than a second end of the silicon waveguide core. The silicon waveguide core may include a vertical taper and/or a lateral taper.

Abstract: An apparatus for optical coupling between optical fibers and semiconductor waveguides and method of use thereof. The optical coupler comprises a tapered semiconductor structure having a cross section defined in a plane substantially perpendicular to a direction of propagation of light, which cross section has a dimension accurate to approximately 50 nanometer tolerance. The coupler has an optical index of refraction. The coupler has adjacent thereto material having an optical index less than that of the semiconductor, the adjacent material confining light within the semiconductor structure. In an exemplary embodiment, an optical communication device has two optical couplers disposed one at each end of a semiconductor waveguide to convey an optical communication from a source at one end to receiver at the other. In a further exemplary embodiment, a plurality of optical communication devices are disposed on a single semiconductor substrate.

Abstract: A miniature monolithic optical demultiplexer that comprises a dispersive optical element and a wavelength filter array. The miniature monolithic optical DWDM demultiplexer can be fabricated using micro- and nano-scale techniques common to the semiconductor industry. The operating principles and some characteristics of the DWDM demultiplexer are described. The device will be useful in the field of optical communication as a component within networks that perform all of the necessary switching, adding, dropping, and manipulating of optical signals entirely in the optical domain. With the inclusion of additional components, exemplary optical communication devices that can be built using the DWDM demultiplexer include optical add/drop multiplexers (OADM), Dense Wavelength Division Multiplexing (DWDM) routers, tunable filters, optical cross connects, and the like.

Abstract: A miniature monolithic optical add-drop multiplexer that comprises a dispersive optical element, a wavelength filter array and a diverter. The miniature monolithic optical DWDM add-drop multiplexer can be fabricated using micro- and nano-scale techniques common to the semiconductor industry. The operating principles and some characteristics of the DWDM add-drop multiplexer are described. The device will be useful in the field of optical communication as a component within networks that perform all of the necessary switching, adding, dropping, and manipulating of optical signals entirely in the optical domain.

Abstract: An optical bench that provides a core component for a communication system that performs all of the necessary switching, adding, dropping, and manipulating of optical signals entirely in the optical domain. The optical bench comprises a dispersive optical element and a spatial light modulator. Various devices that are useful in the field of optical communication can be produced using the optical bench apparatus as a core component, with the addition of other components to the optical bench. Exemplary optical communication devices that can be built using the optical bench include optical add/drop multiplexers (OADM), Dense Wavelength Division Multiplexing (DWDM) routers, tunable filters, tunable laser sources, optical cross connects, and the like.

Abstract: A miniature monolithic optical demultiplexer that comprises a dispersive optical element and a wavelength filter array. The miniature monolithic optical DWDM demultiplexer can be fabricated using micro- and nano-scale techniques common to the semiconductor industry. The operating principles and some characteristics of the DWDM demultiplexer are described. The device will be useful in the field of optical communication as a component within networks that perform all of the necessary switching, adding, dropping, and manipulating of optical signals entirely in the optical domain. With the inclusion of additional components, exemplary optical communication devices that can be built using the DWDM demultiplexer include optical add/drop multiplexers (OADM), Dense Wavelength Division Multiplexing (DWDM) routers, tunable filters, optical cross connects, and the like.

Abstract: A miniature monolithic optical add-drop multiplexer that comprises a dispersive optical element, a wavelength filter array and a diverter. The miniature monolithic optical DWDM add-drop multiplexer can be fabricated using micro- and nano-scale techniques common to the semiconductor industry. The operating principles and some characteristics of the DWDM add-drop multiplexer are described. The device will be useful in the field of optical communication as a component within networks that perform all of the necessary switching, adding, dropping, and manipulating of optical signals entirely in the optical domain.

Abstract: Disclosed is a system for regulating the efficiency of a combustion process by detecting radiant energy emitted from ash particles entrained in the gas stream exiting the combustion chamber of a boiler or incinerator. The intensity of selected wavelengths of light emitted from the particles is indicative of the temperature of the particles. The change in the intensities of the selected wavelengths of light, and thus of the temperature of the gas stream at the furnace exit, is monitored, and a feedback control mechanism is used to regulate one or more combustion, pollution control, or heat transfer parameters thereby maximizing the thermal efficiency of the combustion process in the boiler or incinerator.

Abstract: Disclosed is a system for regulating the efficiency of a combustion process by detecting radiant energy emitted from ash particles entrained in the gas stream exiting the combustion chamber of a boiler or incinerator. The intensity of selected wavelengths of light emitted from the particles is indicative of the temperature of the particles. The change in the intensities of the selected wavelengths of light, and thus of the temperature of the gas stream at the furnace exit, is monitored, and a feedback control mechanism is used to regulate one or more combustion, pollution control, or heat transfer parameters thereby maximizing the thermal efficiency of the combustion process in the boiler or incinerator.

Abstract: A coated substrate manufactured by applying a layer of a material to the substrate and generating thermal and pressure waves in the layer by exposing the layer to high intensity, short duration laser radiation, and the process of manufacturing such a coated substrate. The laser radiation is applied in an intensity range that creates an instantaneous surface vaporization of the layer material that in turn drives a pressure wave into the layer. The pressure wave interacts with the layer-substrate interface to create bonding between them of varying strengths and qualities depending on the intensity and duration of the initial laser pulse. A thermal wave is created in some regimes of operation, or results from compressional heating of the layer by the pressure wave, and is of sufficient energy to contribute to the bonding at the interface.

Abstract: An optical system for direct measurement of vorticity in a flowing fluid is disclosed. Spherical particles suspended in the flow rotate with an angular velocity that is accurately equal to half the local vorticity; thus, measurements of the rotation rates of such particles indicate the vorticity. The particles are transparent, and preferably are less than 50 .mu.m diameter, and each contains embedded planar crystal mirrors. The particles are suspended in a refractive index matched liquid. Measurement of the particle rotation rate and thus the vorticity of the fluid is preferably accomplished by measuring the rotation rates of reflections of one or more light beams from the planar mirrors. The measurements may be carried out using any system of position sensitive optical detectors such as photo sensitive devices screened by suitable slits or photo diode arrays.