Abstract: An optical sensor includes an optic fiber optically coupled to a cavity. An optical path is defined from the fiber, across the cavity, and reflected back across the cavity back into the fiber. The cavity is an open cavity that is in fluid communication with an environment ambient to the cavity for detection of changes in index of refraction inside the cavity due to whether the environment ambient to the cavity is gaseous or liquid.

Abstract: A system includes an optical pressure sensor. A controller is operatively connected to receive input from the optical pressure sensor. An output connection is operatively connected to communicate output data from the controller. The controller includes machine readable 5 instructions configured to cause the controller to receive data from an optical pressure sensor, detect an accumulation of contaminant on the optical pressure sensor, and initiate a corrective action through the output connection in response to detecting the accumulation of contaminant.

Abstract: A method includes receiving wavelength domain data for a time step, performing a Discrete Fourier Transform (DFT) to transform the wavelength domain data for the time step into frequency domain data for the time step only for the limited set of frequency bins associated with a frequency of interest, calculating pressure based on the frequency domain data for the time step, and updating the frequency of interest and the limited set of frequency bins. The method includes repeating receiving wavelength data for subsequent time steps, performing a DFT to transform the wavelength data for the respective subsequent time steps, calculating pressure for each subsequent time step, and updating the frequency of interest and limited set of frequency bins for each subsequent time step. The method includes outputting pressure data based on calculating pressure for the subsequent time steps.

Abstract: A load sensing system for sensing a load on a structure can include an optical load sensing element configured to change an optical state based on a force applied thereto, an optical source operatively connected to the optical load sensing element and configured to input an input optical signal to the optical load element, and an optical detector configured to receive a returned optical signal from the optical load sensing element. The optical detector can be configured to detect one or more frequency peaks of the returned optical signal and to use the one or more frequency peaks of the returned optical signal to correlate to a load value of the load and output the load value indicative of the load.

Abstract: Apparatus and associated methods relate to determining the wavelength of a narrow-band light beam. The narrow-band light beam is passed through an optical filter. The optical filter has complementary and monotonically-varying transmission and reflection coefficients within a predetermined band of wavelengths. The predetermined band of wavelengths includes the wavelength of the narrow-band light beam. A first photodetector detects amplitude of a first portion of the narrow-band light beam transmitted by the optical filter. A second photodetector detects amplitude of a second portion of the narrow-band light beam reflected by the optical filter. The wavelength of the narrow-band light beam is determined, based on a ratio of the determined amplitudes of the first and second portions of the narrow-band light beam transmitted and reflected, respectively.

Abstract: A switching device includes an insulated gate bipolar transistor (IGBT) or MOSFET having a gate, an emitter, and a collector configured to allow current to pass between the emitter and the collector based on voltage applied to the gate. A stack of alternating layers of photo-sensitive p-n junction layers and insulating layers stacked on the gate for optical switching control of voltage through the IGBT or MOSFET.

Abstract: A load sensing system for sensing a load on a structure can include an optical load sensing element configured to change an optical state based on a force applied thereto, an optical source operatively connected to the optical load sensing element and configured to input an input optical signal to the optical load element, and an optical detector configured to receive a returned optical signal from the optical load sensing element. The optical detector can be configured to detect one or more frequency peaks of the returned optical signal and to use the one or more frequency peaks of the returned optical signal to correlate to a load value of the load and output the load value indicative of the load.

Abstract: An optically powered pressure sensor for sensing pressure of a liquid in a tank includes a hermetically sealed housing with at least a portion of the housing having a diaphragm, at least one sensor within the hermetically sealed housing, at least one optical emitter, and a photocell array. The hermetically sealed housing forms at least a portion of a hermetically sealed wall of the tank. The at least one sensor within the hermetically sealed housing is configured to sense the pressure of the liquid. The at least one optical emitter is configured to transmit data corresponding to the sensed pressure. The photocell array is configured to receive light and provide power to the at least one sensor and the at least one optical emitter.

Abstract: A liquid level detection system for determining a liquid level includes a level sensor configured to be at least partially disposed in a liquid storage vessel and exposed to liquid. A first optoelectronic interface is operatively connected to the level sensor for providing power thereto. A second optoelectronic interface is operatively connected to the first optoelectronic interface. A fiber optic cable optically connects the first optoelectronic interface to the second optoelectronic interface to provide photonic power to the first optoelectronic interface and to transmit data from the first optoelectronic interface to the second optoelectronic interface.

Abstract: A liquid measurement system for determining a quantity of a liquid within a tank includes a pressurized air supply, a valve connected to the pressurized air supply with the valve able to introduce a known mass of air into the tank, a pressure sensor able to measure the change in air pressure within the tank, and a processor operatively connected to the valve and the pressure sensor. The processor is able to determine the volume of the liquid within the tank from the known mass of air introduced into the tank and the change in air pressure within the tank.

Abstract: Apparatus and associated methods relate to determining the wavelength of a narrow-band light beam. Two portions of the narrow-band light beam are projected onto two dissimilar photodetectors, respectively. The two dissimilar photodetectors have dissimilar spectral responses over a domain of wavelengths that includes the wavelength of the narrow-band light beam. Each of the two dissimilar photodetectors generates an output signal indicative of a photocurrent induced by the projection of the portion of the narrow-band light beam thereon. A ratio of the differences between the photocurrents to the sum of the photocurrents of the two dissimilar photodetectors is determined. The determined ratio is a monotonic function of wavelength over the domain wavelengths including the wavelength of the narrow-band light beam. The determined ratio is thereby indicative of the wavelength of the narrow-band light beam.

Abstract: An optically powered pressure sensor for sensing pressure of a liquid in a tank includes a hermetically sealed housing with at least a portion of the housing having a diaphragm, at least one sensor within the hermetically sealed housing, at least one optical emitter, and a photocell array. The hermetically sealed housing forms at least a portion of a hermetically sealed wall of the tank. The at least one sensor within the hermetically sealed housing is configured to sense the pressure of the liquid. The at least one optical emitter is configured to transmit data corresponding to the sensed pressure. The photocell array is configured to receive light and provide power to the at least one sensor and the at least one optical emitter.

Abstract: Apparatus and associated methods relate to determining the wavelength of a narrow-band light beam. Two portions of the narrow-band light beam are projected onto two dissimilar photodetectors, respectively. The two dissimilar photodetectors have dissimilar spectral responses over a domain of wavelengths that includes the wavelength of the narrow-band light beam. Each of the two dissimilar photodetectors generates an output signal indicative of a photocurrent induced by the projection of the portion of the narrow-band light beam thereon. A ratio of the differences between the photocurrents to the sum of the photocurrents of the two dissimilar photodetectors is determined. The determined ratio is a monotonic function of wavelength over the domain wavelengths including the wavelength of the narrow-band light beam. The determined ratio is thereby indicative of the wavelength of the narrow-band light beam.

Abstract: Apparatus and associated methods relate to determining the wavelength of a narrow-band light beam. The narrow-band light beam is passed through an optical filter. The optical filter has complementary and monotonically-varying transmission and reflection coefficients within a predetermined band of wavelengths. The predetermined band of wavelengths includes the wavelength of the narrow-band light beam. A first photodetector detects amplitude of a first portion of the narrow-band light beam transmitted by the optical filter. A second photodetector detects amplitude of a second portion of the narrow-band light beam reflected by the optical filter. The wavelength of the narrow-band light beam is determined, based on a ratio of the determined amplitudes of the first and second portions of the narrow-band light beam transmitted and reflected, respectively.

Abstract: A liquid measurement system for determining a quantity of a liquid within a tank includes a pressurized air supply, a valve connected to the pressurized air supply with the valve able to introduce a known mass of air into the tank, a pressure sensor able to measure the change in air pressure within the tank, and a processor operatively connected to the valve and the pressure sensor. The processor is able to determine the volume of the liquid within the tank from the known mass of air introduced into the tank and the change in air pressure within the tank.

Abstract: A method for accurately determining a density of a fuel includes obtaining dielectric constant versus density characteristics of the fuel at a first location and measuring a dielectric constant of the fuel at a second location. The environmental conditions at the second location differ from environmental conditions at the first location. Density of the fuel at the second location is inferred using the dielectric constant of the fuel at the second location and the dielectric constant versus density characteristics of the fuel at the first location.

Abstract: Aircraft fuel tank inerting systems and methods are provided. The aircraft fuel tank inerting systems include a fuel tank having fuel therein, an evaporator container fluidly connected to the fuel tank and arranged to receive inerting fuel from the fuel tank, the evaporator container evaporating the inerting fuel to generate a first reactant, a second reactant source arranged to supply a second reactant, and a catalyst fluidly connected to the evaporator container and arranged to receive the first reactant and the second reactant, wherein the catalyst includes a catalyst material to induce a chemical reaction between the first reactant and the second reactant to generate an inert gas, wherein the inert gas is supplied into an ullage of the fuel tank.

Abstract: A remote data concentrator includes a front end interface, a plurality of back end interfaces and a control circuit. The front end interface is configured to receive optical energy as input and provide optical data as output to an optical link. The plurality of back end interfaces are configured to connect to a plurality of sensors. Each of the plurality of back end interfaces are configured to provide sensor power to the plurality of sensors and receive sensor data from the plurality of sensors. The control circuit is configured to provide power from the front end interface to the plurality of back end interfaces and to provide the sensor data from the plurality of back end interfaces to the front end interface.

Abstract: A remote data concentrator includes a front end interface, a plurality of back end interfaces and a control circuit. The front end interface is configured to receive optical energy as input and provide optical data as output to an optical link. The plurality of back end interfaces are configured to connect to a plurality of sensors. Each of the plurality of back end interfaces are configured to provide sensor power to the plurality of sensors and receive sensor data from the plurality of sensors. The control circuit is configured to provide power from the front end interface to the plurality of back end interfaces and to provide the sensor data from the plurality of back end interfaces to the front end interface.

Abstract: A liquid level detection system for determining a liquid level includes a level sensor configured to be at least partially disposed in a liquid storage vessel and exposed to liquid. A first optoelectronic interface is operatively connected to the level sensor for providing power thereto. A second optoelectronic interface is operatively connected to the first optoelectronic interface. A fiber optic cable optically connects the first optoelectronic interface to the second optoelectronic interface to provide photonic power to the first optoelectronic interface and to transmit data from the first optoelectronic interface to the second optoelectronic interface.