Abstract: A portable flow measuring apparatus measures the speed of sound and/or vortical disturbances propagating in a fluid flow to determine a parameter of the flow propagating through a pipe. The apparatus includes a sensing device that includes an array of pressure sensors, which may be removable, used to measure the acoustic and convective pressure variations in the flow to determine a desired parameter. A portable processing instrument processes the signals provided by the sensing array to provide an output signal indicative of a parameter of the fluid flow. The portable processing instrument includes a processor having appropriate processing algorithms to determine the desired or selected parameter(s) of the process flow 12. The portable processing instrument has a user interface to permit the user to select the parameters to be measured in the process flow, and/or more importantly, to enable the user to modify particular parameters or functions in the processor 30 and/or processing algorithms.

Abstract: A smart node is provided for use in an optical communications network wherein the smart node comprising dynamically reconfigurable optical signal manipulation devices in combination with sensing devices and processors to provide real time closed and open loop control of various channels of the network.

Abstract: Various methods are described which increase the efficiency and accuracy of a signal processor in determining parameters of a fluid using signals output by a spatial array of sensors disposed along a pipe. In one aspect, parameters used for calculating the temporal Fourier transform of the pressure signals, specifically the amount or duration of the data that the windowing function is applied to and the temporal frequency range, are adjusted in response to the determined parameter. In another aspect, an initialization routine estimates flow velocity so the window length and temporal frequency range can be initially set prior to the full array processing. In another aspect, the quality of one or more of the parameters is determined and used to gate the output of the apparatus in the event of low confidence in the measurement and/or no flow conditions. In another aspect, a method for determining a convective ridge of the pressure signals in the k-? plane is provided.

Abstract: An apparatus 10 is provided that measures the speed of sound propagating in a multiphase mixture to determine parameters, such as mixture quality, particle size, vapor/mass ratio, liquid/vapor ratio, mass flow rate, enthalpy and volumetric flow rate of the flow in a pipe or unconfined space, for example, using acoustic and/or dynamic pressures. The apparatus includes a pair of ultrasonic transducers disposed axially along the pipe for measuring the transit time of an ultrasonic signal to propagate from one ultrasonic transducer to the other ultrasonic transducer. A signal process, responsive to said transit time signal, provides a signal representative of the speed of sound of the mixture. An SOS processing unit then provides an output signal indicative of at least one parameter of the mixture flowing through the pipe. The frequency of the ultrasonic signal is sufficiently low to minimize scatter from particle/liquid within the mixture.

Abstract: A device for measurement of entrained and dissolved gas has a first module arranged in relation to a process line for providing a first signal containing information about a sensed entrained air/gas in a fluid or process mixture flowing in the process line at a process line pressure. The device features a combination of a bleed line, a second module and a third module. The bleed line is coupled to the process line for bleeding a portion of the fluid or process mixture from the process line at a bleed line pressure that is lower than the process pressure. The second module is arranged in relation to the bleed line, for providing a second signal containing information about a sensed bleed line entrained air/gas in the fluid or process mixture flowing in the bleed line.

Abstract: The present invention provides a new and unique method for increasing the photosensitivity of a large diameter optical waveguide having a cross-section of at least about 0.3 millimeters. The method features loading the large diameter optical waveguide with a photosensitizing gas at a pressure at least about 4000 pounds per square inch (PSI) at a temperature of at least about 250E Celsius. The photosensitizing gas may be hydrogen, Deuterium or other suitable gas. The method also includes the step of using a particular large diameter optical waveguide having a diameter of greater than 0.9 millimeters. The method may be used as part of a process for writing a Bragg grating in an inner core or a cladding of the large diameter optical waveguide.

Abstract: An apparatus 10,110 is provided that measures the speed of sound or acoustic disturbances propagating in a fluid or mixture having entrained gas/air to determine the gas volume fraction of the flow 12 propagating through a pipe 14. The apparatus includes an array of pressure sensors disposed axially along the length of the pipe. The apparatus measures the speed of sound propagating through the fluid to determine the gas volume fraction of the mixture using adaptive array processing techniques to define an acoustic ridge in the k-? plane. The slope of the acoustic ridge 61 defines the speed of sound propagating through the fluid in the pipe.

Abstract: An apparatus 10,70 and method is provided that includes a spatial array of unsteady pressure sensors 15–18 placed at predetermined axial locations x1–xN disposed axially along a pipe 14 for measuring at least one parameter of a saturated vapor/liquid mixture 12, such as steam, flowing in the pipe 14. The pressure sensors 15–18 provide acoustic pressure signals P1(t)–PN(t) to a signal processing unit 30 which determines the speed of sound amix propagating through of the saturated vapor/liquid mixture 12 in the pipe 14 using acoustic spatial array signal processing techniques. The primary parameters to be measured include vapor/liquid concentration (i.e., steam wetness or steam quality), vapor/liquid mixture volumetric flow, mass flow, enthalpy, density and liquid droplet size. Frequency based sound speed is determined utilizing a dispersion model to determine the parameters of interest.

Abstract: An dynamic optical filter 10 is provided to selectively attenuate or filter a wavelength band(s) of light (i.e., optical channel(s)) or a group(s) of wavelength bands of an optical WDM input signal 12. The optical filter is controllable or programmable to selectively provide a desired filter function. The optical filter 10 includes a spatial light modulator 36, which comprises an array of micromirrors 52 that effectively forms a two-dimensional diffraction grating mounted in a retro-reflecting configuration. Each optical channel 14 is dispersed separately or overlappingly onto the array of micro-mirrors 52 along a spectral axis or direction 55 such that each optical channel or group of optical channels are spread over a plurality of micromirrors to effectively pixelate each of the optical channels or input signal.

Abstract: A method and apparatus is provided for detecting peaks in an optical signal. The method comprises the three basic steps of: (1) sampling the optical signal to obtain sampled data containing information about the optical signal; (2) applying a cross-correlation filter on the sampled data to obtain cross-correlated data containing information about one or more peaks in the optical signal; and (3) detecting the one or more peaks in the optical signal based on the cross-correlation data. In one embodiment, the cross-correlation filter has an average value that is less than zero. The step of applying the cross-correlation filter includes reducing random noise present in the sampled data to remove quasi-dc components from the sampled data.

Abstract: A large diameter D-shaped optical waveguide device 9, includes an optional circular waveguide portion 11 and a D-shaped waveguide portion 10 having at least one core 12 surrounded by a cladding 14. A portion of the waveguide device 9 has a generally D-shaped cross-section and has transverse waveguide dimension d2 greater than about 0.3 mm. At least one Bragg grating 16 may be impressed in the waveguide 10 and/or more than one grating or pair of gratings may be used and more than one core may be used. The device 9 provides a sturdy waveguide platform for coupling light into and out of waveguides and for attachment and alignment to other waveguides, for single and multi-core applications. The core and/or cladding 12,14 may be doped with a rare-earth dopant and/or may be photosensitive. At least a portion of the core 12 may be doped between a pair of gratings 50,52 to form a fiber laser or the grating 16 or may be constructed as a tunable DFB fiber laser or an interactive fiber laser within the waveguide 10.

Abstract: In industrial sensing applications at least one parameter of at least one fluid in a pipe 12 is measured using a spatial array of acoustic pressure sensors 14,16,18 placed at predetermined axial locations x1, x2, x3 along the pipe 12. The pressure sensors 14,16,18 provide acoustic pressure signals P1(t), P2(t), P3(t) on lines 20,22,24 which are provided to signal processing logic 60 which determines the speed of sound amix of the fluid (or mixture) in the pipe 12 using acoustic spatial array signal processing techniques with the direction of propagation of the acoustic signals along the longitudinal axis of the pipe 12. Numerous spatial array-processing techniques may be employed to determine the speed of sound amix. The speed of sound amix is provided to logic 48, which calculates the percent composition of the mixture, e.g., water fraction, or any other parameter of the mixture, or fluid, which is related to the sound speed amix. The logic 60 may also determine the Mach number Mx of the fluid.

Abstract: A fiber optic pressure sensor for measuring unsteady pressures within a pipe include at least one optical fiber disposed circumferentially around a portion of a circumference of the pipe, which provides an optical signal indicative of the length of the optical fiber. An optical instrument measures the change in length of the optical fiber to determine the unsteady pressure within the pipe. The pressure sensor may include a plurality of optical fiber sections disposed circumferentially around a portion of the circumference of the pipe that are optically connected together by optical fiber sections disposed axially along the pipe. The optical fiber sections may include fiber Bragg gratings having substantially the same or different reflection wavelengths to permit for example the sensors to be axially distributed along the fiber using wavelength division multiplexing and/or time division multiplexing.

Abstract: A reconfigurable optical blocking filter deletes a desired optical channel(s) from an optical WDM input signal, and includes a spatial light modulator having a micro-mirror device with a two-dimensional array of micro-mirrors that tilt between first and second positions in a “digital” fashion in response to a control signal provided by a controller in accordance with a switching algorithm and an input command. A collimators, diffraction grating, and Fourier lens, collectively collimate, separate and focus the optical input channels onto the array of micro-mirrors. The optical channel is focused on the micro-mirrors onto a plurality of micro-mirrors of the micro-mirror device, which effectively pixelates the optical channels. To delete an input channel of the optical input signal, micro-mirrors associated with each desired input channel are tilted to reflect the desired input channel away from the return path.

Abstract: A method is provided for precise and repeatable location of one or more Bragg gratings in a large diameter optical waveguide having a cross-section of at least about 0.3 millimeters, featuring the steps of: defining a reference location on a fixed placement datum arranged on a waveguide fixture device; defining one or more desired locations on a large diameter optical waveguide arranged on the waveguide fixture location in relation to the reference location; and writing one or more Bragg gratings in the large diameter optical waveguide at the one or more desired locations based on the reference location on the fixed placement datum. The step of defining the reference location may include marking the fixed placement datum with a scribe mark thereon; and securing the fixed placement datum in a groove in a waveguide fixture device.

Abstract: A chromatic dispersion compensation device selectively delays a respective portion of spectral sections of each respective optical channel of an optical WDM input signal to compensate each optical channel for dispersion compensation, and includes a spatial light modulator having a micromirror device with a two-dimensional array of micromirrors. The micromirrors tilt or flip between first and second positions in a “digital” fashion in response to a control signal provided by a controller in accordance with a switching algorithm and an input command. A collimator, diffraction gratings, and Fourier lens collectively collimate, disperse and focus the optical input channels onto the array of micromirrors. Each optical channel is focused onto micromirrors of the micromirror device, which effectively pixelates the optical channels. To compensate an optical channel for chromatic dispersion, a portion of the spectral sections of each channel is delayed a desired time period by tilting an array of mirrors (i.e.

Abstract: An apparatus 10 and method is provided that includes a spatial array of unsteady pressure sensors 15-18 placed at predetermined axial locations x1-xN disposed axially along a pipe 14 for measuring at least one parameter of a solid particle/fluid mixture 12 flowing in the pipe 14. The pressure sensors 15-18 provide acoustic pressure signals P1(t)-PN(t) to a signal processing unit 30 which determines the speed of sound amix(?) of the particle/fluid mixture 12 in the pipe 14 using acoustic spatial array signal processing techniques. The primary parameters to be measured include fluid/particle concentration, fluid/particle mixture volumetric flow, and particle size. Frequency based sound speed is determined utilizing a dispersion model to determine the parameters of interest.

Abstract: A reconfigurable optical interleaver/deinterleaver device combines/separates a pair of optical input signals from and/or to an optical WDM input signal. The interleaver device includes a spatial light modulator having a micro-mirror device with a two-dimensional array of micro-mirrors that flip between first and second positions in a “digital” fashion in response to a control signal provided by a controller in accordance with a switching algorithm and an input command. A pair of collimators, diffraction gratings and Fourier lens collectively collimate, separate and focus the optical input channels and optical add channels onto the array of micro-mirrors. Each optical channel is focused on a plurality of micro-mirrors of the micro-mirror device, which effectively pixelates the optical channels.

Abstract: A Fabry-Perot optical device, including: a large-diameter elongated optical waveguide having a core and having an air gap region disposed along the longitudinal axis of the waveguide, and with the air gap region enclosed by end faces substantially perpendicular to the longitudinal axis of the waveguide, the waveguide also having a cavity delimited on at least one side by an endface of the air gap, wherein the endface is at least partially reflective. From another perspective, the invention provides an apparatus including: a force-applying assembly, responsive to a control signal containing information about a selected resonated wavelength or a selected filtered wavelength derived from an optical signal, for providing a force; and a Fabry-Perot optical structure, responsive to the force, and further responsive to the optical signal, for providing a Fabry-Perot optical structure signal either with the selected resonated wavelength or without the selected filtered wavelength.

Abstract: Flow rate measurement system includes two measurement regions 14,16 located an average axial distance ?X apart along the pipe 12, the first measurement region 14 having two unsteady pressure sensors 18,20, located a distance X1 apart, and the second measurement region 16, having two other unsteady pressure sensors 22,24, located a distance X2 apart, each capable of measuring the unsteady pressure in the pipe 12. Signals from each pair of pressure sensors 18,20 and 22,24 are differenced by summers 44,54, respectively, to form spatial wavelength filters 33,35, respectively. Each spatial filter 33,35 filters out acoustic pressure disturbances Pacoustic and other long wavelength pressure disturbances in the pipe 12 and passes short-wavelength low-frequency vortical pressure disturbances Pvortical associated with the vortical flow field 15. The spatial filters 33,35 provide signals Pas1,Pas2 to band pass filters 46,56 that filter out high frequency signals.