Abstract: A solid state photomultiplier includes at least one microcell configured to generate an initial analog signal when exposed to optical photons. The solid state photomultiplier further includes a quench circuit electrically coupled with the at least one microcell. The quench circuit includes at least one quench resistor configured to exhibit a substantially constant temperature coefficient of resistance over a selected temperature range.

Abstract: A distributed gas detection system includes one or more hollow core fibers disposed in different locations, one or more solid core fibers optically coupled with the one or more hollow core fibers and configured to receive light of one or more wavelengths from a light source, and an interrogator device configured to receive at least some of the light propagating through the one or more solid core fibers and the one or more hollow core fibers. The interrogator device is configured to identify a location of a presence of a gas-of-interest by examining absorption of at least one of the wavelengths of the light at least one of the hollow core fibers.

Abstract: A distributed gas detection system includes one or more hollow core fibers disposed in different locations, one or more solid core fibers optically coupled with the one or more hollow core fibers and configured to receive light of one or more wavelengths from a light source, and an interrogator device configured to receive at least some of the light propagating through the one or more solid core fibers and the one or more hollow core fibers. The interrogator device is configured to identify a location of a presence of a gas-of-interest by examining absorption of at least one of the wavelengths of the light at least one of the hollow core fibers.

Abstract: A silicon photomultiplier array includes a plurality of microcells within the photomultiplier array and located on the silicon wafer, the plurality of microcells arranged in rows and columns, each of the plurality of microcells including an output port, and configured to provide a pulse waveform having pulse characteristics, at least one repatterning dielectric layer in contact with a silicon wafer layer back surface, the silicon wafer having an active surface opposed to the back surface, and a plurality of respective through-silicon-vias (TSVs) coupling the output port of respective ones of the plurality of microcells on the active surface of the silicon wafer to a plurality of respective circuit traces on the at least one repatterning dielectric layer disposed on the back surface of the silicon wafer. A method for producing the silicon photomultiplier array is also disclosed.

Abstract: Microstructured optical fiber (MOF) includes a cladding extending a length between first and second ends. The cladding includes an inner porous microstructure that at least partially surrounds a hollow core. A perimeter contour of the hollow core has a non-uniform radial distance from a center axis of the cladding such that first segments of the cladding along the perimeter contour have a shorter radial distance from the center axis relative to second segments of the cladding along the perimeter contour. The cladding receives and propagates light energy through the hollow core, and the inner porous microstructure substantially confines the light energy within the hollow core. The cladding defines at least one port hole that extends radially from an exterior surface of the cladding to the hollow core. Each port hole penetrates the perimeter contour of the hollow core through one of the second segments of the cladding.

Abstract: A solid state photomultiplier includes at least one microcell configured to generate an initial analog signal when exposed to optical photons. The solid state photomultiplier further includes a quench circuit electrically coupled with the at least one microcell. The quench circuit includes at least one quench resistor configured to exhibit a substantially constant temperature coefficient of resistance over a selected temperature range.

Abstract: Microstructured optical fiber (MOF) includes a cladding extending a length between first and second ends. The cladding includes an inner porous microstructure that at least partially surrounds a hollow core. A perimeter contour of the hollow core has a non-uniform radial distance from a center axis of the cladding such that first segments of the cladding along the perimeter contour have a shorter radial distance from the center axis relative to second segments of the cladding along the perimeter contour. The cladding receives and propagates light energy through the hollow core, and the inner porous microstructure substantially confines the light energy within the hollow core. The cladding defines at least one port hole that extends radially from an exterior surface of the cladding to the hollow core. Each port hole penetrates the perimeter contour of the hollow core through one of the second segments of the cladding.

Abstract: A pressure sensing cable in one embodiment includes a polarization maintaining (PM) optic fiber having a length; and a Fiber Bragg Grating (FBG) pair formed in the PM optic fiber. The FBG pair includes a first FBG formed at a location along the length of the optic fiber. The first FBG defines a first wavelength range at which the first FBG is reflective. The FBG pair also includes a second FBG spaced a distance from the first FBG to define a FBG cavity extending between the first FBG and the second FBG. The second FBG defines a second wavelength range at which the second FBG is reflective. The first wavelength range of the first FBG and the second wavelength range of the second FBG at least partially overlap.

Abstract: Embodiments of a photodiode array are provided herein. In some embodiments, a photodiode array may include a semiconductor layer configured to convert photons into analog electrical signals; and a passive layer having a first surface and a second surface disposed opposite the first surface, wherein the semiconductor layer is coupled to the first surface, and wherein the passive layer is configured to have a signal receiving component coupled directly to the second surface of the passive layer.

Abstract: A method and an apparatus for detecting photons are disclosed. The apparatus includes a solid state photo multiplier device having a plurality of microcells that have a band gap greater than about 1.7 eV at 25° C. The solid state photo multiplier device further includes an integrated quenching device and a thin film coating associated with each of the microcells. The solid state photo multiplier device disclosed herein operates in a temperature range of about ?40° C. to about 275° C.

Abstract: A sensor interrogation unit in one embodiment includes a control module, a reading module, and a determination module. The control module is configured to control one or more lasers to provide a pulsed signal to at least one sensor. Each period of the pulsed signal has a first component having a first intensity and a second component having a second intensity that is lower than the first intensity. The reading module is configured to receive at least one return signal comprising reflections of the pulsed signal from the at least one sensor, to read one of the first component or the second component, and to provide frequency information based on the read reflections. The determination module is configured to determine at least one resonant frequency of the at least one sensor based on the frequency information.

Abstract: A pressure sensing cable in one embodiment includes a polarization maintaining (PM) optic fiber having a length; and a Fiber Bragg Grating (FBG) pair formed in the PM optic fiber. The FBG pair includes a first FBG formed at a location along the length of the optic fiber. The first FBG defines a first wavelength range at which the first FBG is reflective. The FBG pair also includes a second FBG spaced a distance from the first FBG to define a FBG cavity extending between the first FBG and the second FBG. The second FBG defines a second wavelength range at which the second FBG is reflective. The first wavelength range of the first FBG and the second wavelength range of the second FBG at least partially overlap.