Optical waveguide feedthrough assembly

An optical waveguide feedthrough assembly passes at least one optical waveguide through a bulk head, a sensor wall, or other feedthrough member. The optical waveguide feedthrough assembly comprises a cane-based optical waveguide that forms a glass plug sealingly disposed in a feedthrough housing. For some embodiments, the optical waveguide includes a tapered surface biased against a seal seat formed in the housing. The feedthrough assembly can include an annular gold gasket member disposed between the tapered surface and the seal seat. The feedthrough assembly can further include a backup seal. The backup seal comprises an elastomeric annular member disposed between the glass plug and the housing. The backup seal may be energized by a fluid pressure in the housing. The feedthrough assembly is operable in high temperature and high pressure environments.

Optical transducer with integrated feedthrough

An optical transducer is provided. A “measuring” portion of the transducer may be exposed to a high pressure and fluids when the optical transducer is deployed (e.g., in a wellbore or other industrial setting). The transducer may include an optical waveguide with a first portion that forms a first seal that isolates an “instrumentation” portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed. The transducer may also include a second seal with a “stack” of material elements that contact a second portion of the optical waveguide to also isolate the instrumentation portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed.

Fiber optic cable for distributed acoustic sensing with increased acoustic sensitivity

Methods and apparatus for performing Distributed Acoustic Sensing (DAS) using fiber optics with increased acoustic sensitivity are provided. Acoustic sensing of a wellbore, pipeline, or other conduit/tube based on DAS may have increased acoustic sensitivity through fiber optic cable design and/or increasing the Rayleigh backscatter property of a fiber's optical core. Some embodiments may utilize a resonant sensor mechanism with a high Q coupled to the DAS device for increased acoustic sensitivity.

FIBER OPTIC CABLE FOR DISTRIBUTED ACOUSTIC SENSING WITH INCREASED ACOUSTIC SENSITIVITY

Methods and apparatus for performing Distributed Acoustic Sensing (DAS) using fiber optics with increased acoustic sensitivity are provided. Acoustic sensing of a wellbore, pipeline, or other conduit/tube based on DAS may have increased acoustic sensitivity through fiber optic cable design and/or increasing the Rayleigh backscatter property of a fiber's optical core. Some embodiments may utilize a resonant sensor mechanism with a high Q coupled to the DAS device for increased acoustic sensitivity. 1. A fiber optic cable used for distributed acoustic sensing (DAS) , comprising:an outer tube;an inner tube surrounded by the outer tube; andone or more optical fibers surrounded by the inner tube, wherein the one or more optical fibers have increased acoustic sensitivity compared to a standard optical fiber.2. The fiber optic cable of claim 1 , wherein at least one of the one or more optical fibers comprise:a core;a cladding surrounding the core; anda fiber coating surrounding the cladding.3. The fiber optic cable of claim 2 , wherein at least one of the one or more optical fibers further comprise holes lengthwise within the cladding.4. The fiber optic cable of claim 3 , wherein the holes enhance strain sensitivity of the one or more optical fibers compared to the standard optical fiber.5. The fiber optic cable of claim 3 , wherein the holes are arranged such that pressures created by acoustic waves are focused on the core.6. The fiber optic cable of claim 1 , wherein at least one of the one or more optical fibers have a smaller diameter compared to the standard optical fiber.7. The fiber optic cable of claim 6 , wherein claim 6 , upon application of pressures created by acoustic waves claim 6 , the smaller diameter provides for increased response of the fibers when compared to the standard optical fiber.8. The fiber optic cable of claim 2 , wherein the fiber coating comprises graded layers with at least one of different materials or different thicknesses.9. The fiber ...

OPTICAL WAVEGUIDE FEEDTHROUGH ASSEMBLY

An optical waveguide feedthrough assembly passes at least one optical waveguide through a bulk head, a sensor wall, or other feedthrough member. The optical waveguide feedthrough assembly comprises a cane-based optical waveguide that forms a glass plug sealingly disposed in a feedthrough housing. For some embodiments, the optical waveguide includes a tapered surface biased against a seal seat formed in the housing. The feedthrough assembly can include an annular gold gasket member disposed between the tapered surface and the seal seat. The feedthrough assembly can further include a backup seal. The backup seal comprises an elastomeric annular member disposed between the glass plug and the housing. The backup seal may be energized by a fluid pressure in the housing. The feedthrough assembly is operable in high temperature and high pressure environments. 1. An optical waveguide feedthrough assembly , comprising:a housing having a bore therethrough with an inward tapering conical surface located along a length of the bore;an optical waveguide element having a plug portion in optical communication with two optical waveguide portions extending from each end of the plug portion;a compression seal element disposed around the plug portion within the bore proximate the conical surface; andan externally threaded bushing mated with an internal threaded portion of the bore of the housing, wherein the bushing is rotatable with respect to the housing to drive the seal element down the conical surface and pack an annulus between the housing and the plug portion.2. The assembly of claim 1 , further comprising a compression driver bushing disposed between the seal element and the threaded bushing.3. The assembly of claim 1 , wherein the plug portion comprises a tapered surface for mating with a complimentary tapered seat disposed in the housing located along a length of the bore.4. The assembly of claim 3 , further comprising an annular gasket member disposed between the ...

OPTICAL TRANSDUCER WITH INTEGRATED FEEDTHROUGH

An optical transducer is provided. A “measuring” portion of the transducer may be exposed to a high pressure and fluids when the optical transducer is deployed (e.g., in a wellbore or other industrial setting). The transducer may include an optical waveguide with a first portion that forms a first seal that isolates an “instrumentation” portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed. The transducer may also include a second seal with a “stack” of material elements that contact a second portion of the optical waveguide to also isolate the instrumentation portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed. 1. An optical transducer , comprising:at least one optical waveguide;at least one sensing element disposed in a portion of the optical waveguide; anda feedthrough element designed to isolate a first portion of the transducer in communication with the sensing element from a second portion of the transducer containing the sensing element, wherein the feedthrough element comprises at least a first seal formed by a first portion of the optical waveguide in contact with a bore extending through a housing of the feedthrough element and a second seal formed by contact between an arrangement of sealing elements with a second portion of the optical waveguide and an inner surface of the feedthrough housing.2. The optical transducer of claim 1 , wherein a first pre-loading force is applied to promote sealing of at least the first seal prior to deployment in an operating environment.3. The optical transducer of claim 2 , wherein a second pre-loading force promotes sealing of the second seal by expanding the sealing elements.4. The optical transducer of claim 2 , further comprising a diagnostic grating disposed in the optical waveguide allowing the first pre-loading force to be measured.5. The optical transducer of claim 2 , wherein:the first ...

ACOUSTICALLY ENHANCED OPTICAL CABLES

Methods and apparatus to control the acoustic properties of optical cables used as in-well oil and gas probes for acoustic monitoring, such as distributed acoustic sensing (DAS). One example aspect provides a solid path for the acoustic wave to propagate from an outside armor layer of the cable to the sensing optical waveguide embedded therein. Another example aspect offers ways to spatially dispose the optical sensing elements to create response delays indicative of the propagation speed and/or direction of an acoustic wave. Yet another example aspect provides ways to utilize additional spectral interrogation to increase ultimate spatial resolution. Yet another example aspect provides ways to locally vary the acoustic properties along the length of the cable. 1. An optical cable comprising:a tube;an optical waveguide disposed in the tube; andone or more solid structures disposed between an inner surface of the tube and an outer surface of the optical waveguide, the one or more solid structures being configured to form at least a portion of a solid path for acoustic waves to travel from an environment outside the tube to the optical waveguide.2. The optical cable of claim 1 , wherein the one or more solid structures contact the optical waveguide.3. The optical cable of claim 1 , wherein the one or more solid structures are attached to the inner surface of the tube at one or more locations along a length of the tube.4. The optical cable of claim 3 , wherein the one or more solid structures are attached to the inner surface of the tube via at least one of solder or an adhesive.5. The optical cable of claim 1 , wherein the one or more solid structures comprise a strip of material having a plurality of bends.6. The optical cable of claim 5 , wherein the plurality of bends are periodic for at least a portion of the strip.7. The optical cable of claim 6 , wherein the plurality of bends have a first periodicity for a first portion of the strip and a second periodicity for ...

OPTICAL TRANSDUCER WITH INTEGRATED FEEDTHROUGH

An optical transducer is provided. A “measuring” portion of the transducer may be exposed to a high pressure and fluids when the optical transducer is deployed (e.g., in a wellbore or other industrial setting). The transducer may include an optical waveguide with a first portion that forms a first seal that isolates an “instrumentation” portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed. The transducer may also include a second seal with a “stack” of material elements that contact a second portion of the optical waveguide to also isolate the instrumentation portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed. 1. A feedthrough assembly , comprising:at least one conductive line; and a housing having a bore extending therethrough;', 'a first seal formed by a first portion of the at least one conductive line in contact with a mating surface of the bore of the housing; and', 'a second seal formed by contact between an arrangement of sealing elements with a second portion of the at least one conductive line and an inner surface of the housing., 'a feedthrough element configured to isolate a first portion of the feedthrough assembly from a second portion of the assembly, wherein the feedthrough element comprises2. The assembly of claim 1 , wherein the feedthrough element further comprises member in contact with a third portion of the at least one conductive line and configured to apply a first pre-loading force to promote sealing of at least the first seal.3. The assembly of claim 2 , wherein the third portion of the at least one conductive line has a greater outer diameter than the first and second portions of the at least one conductive line.4. The assembly of claim 2 , wherein a second pre-loading force is applied to promote sealing of the second seal by expanding the sealing elements.5. The assembly of claim 4 , wherein the sealing ...

FIBER OPTIC CABLE FOR DISTRIBUTED ACOUSTIC SENSING WITH INCREASED ACOUSTIC SENSITIVITY

Methods and apparatus for performing Distributed Acoustic Sensing (DAS) using fiber optics with increased acoustic sensitivity are provided. Acoustic sensing of a wellbore, pipeline, or other conduit/tube based on DAS may have increased acoustic sensitivity through fiber optic cable design and/or increasing the Rayleigh backscatter property of a fiber's optical core. Some embodiments may utilize a resonant sensor mechanism with a high Q coupled to the DAS device for increased acoustic sensitivity. 1. A fiber optic cable suitable for use in distributed acoustic sensing (DAS) , comprising:one or more optical fibers;a first tube surrounding the one or more optical fibers; anda jacket surrounding the first tube, wherein a cross-section of the jacket has a non-circular shape for at least a portion of the length of the jacket.2. The fiber optic cable of claim 1 , wherein the shape of the cross-section of the jacket comprises a square claim 1 , parabolic claim 1 , or elliptical shape.3. The fiber optic cable of claim 1 , wherein two different cross-sections along the length of the jacket have two different shapes.4. The fiber optic cable of claim 1 , wherein two different cross-sections along the length of the jacket have two different sizes.5. The fiber optic cable of claim 1 , wherein the jacket comprises a polymer or a composite.6. The fiber optic cable of claim 1 , further comprising:a second tube surrounding the first tube;a gap between the first tube and the second tube; anda filler material disposed in the gap.7. The fiber optic cable of claim 1 , further comprising:a second tube surrounding the first tube; anda polymer or a composite tubing disposed between the first tube and the second tube.8. (canceled)9. The fiber optic cable of claim 1 , wherein at least one of the one or more optical fibers comprises:a core; anda cladding surrounding the core and comprising holes disposed lengthwise therein.1011-. (canceled)12. The fiber optic cable of claim 9 , wherein the ...

ARRAY TEMPERATURE SENSING METHOD AND SYSTEM

Methods and apparatus enable monitoring conditions in a well-bore using multiple cane-based sensors. The apparatus includes an array of cane-based Bragg grating sensors located in a single conduit for use in the well-bore. For some embodiments, each sensor is located at a different linear location along the conduit allowing for increased monitoring locations along the conduit. 1. A method of manufacturing a sensor array for use in a wellbore , comprising:providing an optical waveguide in a first tubing;cutting the first tubing and the waveguide to create first and second ends of the first tubing;sliding second and third tubing over the first and second ends of the first tubing, respectively;positioning a tubular insert having an outer diameter less than an inner diameter of the second tubing into the second tubing, the tubular insert providing a mount to hold the waveguide;splicing an optical sensor into the waveguide;inserting the optical sensor into the mount; andcoupling the first and second ends of the first tubing back together via the second and third tubing, wherein the coupling encloses the waveguide and the optical sensor.2. The method of claim 1 , wherein the first tubing comprises a metal tube.3. The method of claim 1 , further comprising removing a section of the cut first tubing to create the first and second ends of the first tubing.4. The method of claim 1 , wherein the optical sensor comprises a large diameter optical waveguide having a cladding surrounding a core and wherein an outer diameter of the cladding is at least 0.3 mm.5. The method of claim 4 , wherein a ratio of the outer diameter of the cladding to an outer diameter of the core is in a range from 30:1 to 300:1.6. The method of claim 1 , wherein the optical sensor comprises a Bragg grating.7. The method of claim 1 , wherein the optical sensor has a conical tapered end and wherein splicing the optical sensor into the waveguide comprises fusion splicing the conical tapered end with a cut end ...

ACOUSTICALLY ENHANCED OPTICAL CABLES

Methods and apparatus to control the acoustic properties of optical cables used as in-well oil and gas probes for acoustic monitoring, such as distributed acoustic sensing (DAS). One example aspect provides a solid path for the acoustic wave to propagate from an outside armor layer of the cable to the sensing optical waveguide embedded therein. Another example aspect offers ways to spatially dispose the optical sensing elements to create response delays indicative of the propagation speed and/or direction of an acoustic wave. Yet another example aspect provides ways to utilize additional spectral interrogation to increase ultimate spatial resolution. Yet another example aspect provides ways to locally vary the acoustic properties along the length of the cable. 1. An optical cable comprising:a tube; andan optical waveguide disposed in the tube and comprising a core and a cladding, wherein the core of the optical waveguide has varying angular positions along at least a first portion of the length of the optical cable with respect to an axis of the optical cable.2. The optical cable of claim 1 , wherein the core is disposed helicoidally in the cladding of the optical waveguide.3. The optical cable of claim 1 , wherein the core of the optical waveguide has the varying angular positions and varying radial positions along the at least the first portion of the length of the optical cable with respect to the axis of the optical cable.4. The optical cable of claim 1 , wherein the varying angular positions are known.5. The optical cable of claim 1 , wherein the optical waveguide is disposed helicoidally around the axis of the optical cable.6. The optical cable of claim 5 , wherein the optical waveguide is disposed in a capillary and wherein the capillary is disposed helicoidally around the axis of the optical cable.7. The optical cable of claim 6 , wherein portions of the capillary are attached to an inner surface of the tube.8. The optical cable of claim 1 , wherein the core ...

SMALL PROFILE PRESSURE AND TEMPERATURE GAUGES

Small profile apparatus for pressure and/or temperature sensing within a wellbore are provided. The apparatus may include optical sensing assemblies designed for inclusion in traditional or coiled production tubing deployments and suitable for use in high pressure, high temperature environments. One example assembly generally includes an outer housing, an inner housing at least partially disposed in the outer housing, a port for fluid communication between an internal volume of the inner housing and a volume external to the outer housing, and a large diameter optical waveguide disposed in the internal volume of the inner housing. The waveguide includes a first portion with a first grating and a second portion with a second grating, wherein the outer diameter of the large diameter optical waveguide is at least 300 μm. 1. An optical sensing assembly , comprising:an outer housing;an inner housing at least partially disposed in the outer housing;a port for fluid communication between an internal volume of the inner housing and a volume external to the outer housing; and a first portion with a first grating; and', 'a second portion with a second grating, wherein the outer diameter of the large diameter optical waveguide is at least 300 μm., 'a large diameter optical waveguide disposed in the internal volume of the inner housing, wherein the waveguide comprises2. The assembly of claim 1 , wherein the port is part of the inner housing.3. The assembly of claim 1 , further comprising a glass tubing claim 1 , wherein at least a part of the large diameter optical waveguide is disposed in the glass tubing.4. The assembly of claim 3 , wherein the glass tubing comprises gold-plated glass.5. The assembly of claim 3 , wherein an enclosed volume between the large diameter optical waveguide and the glass tubing is filled with air.6. The assembly of claim 1 , wherein the first portion has a greater outer diameter than the second portion and wherein the outer diameter of the second ...

OPTICAL WAVEGUIDE FEEDTHROUGH ASSEMBLY

An optical waveguide feedthrough assembly passes at least one optical waveguide through a bulk head, a sensor wall, or other feedthrough member. The optical waveguide feedthrough assembly comprises a cane-based optical waveguide that forms a glass plug sealingly disposed in a feedthrough housing. For some embodiments, the optical waveguide includes a tapered surface biased against a seal seat formed in the housing. The feedthrough assembly can include an annular gold gasket member disposed between the tapered surface and the seal seat. The feedthrough assembly can further include a backup seal. The backup seal comprises an elastomeric annular member disposed between the glass plug and the housing. The backup seal may be energized by a fluid pressure in the housing. The feedthrough assembly is operable in high temperature and high pressure environments. 15-. (canceled)6. An optical waveguide feedthrough assembly , comprising:a housing having a face and a bore extending therethrough;an optical waveguide element having a sealing surface for mating with the face, wherein the optical waveguide element has a core and cladding; anda biasing member configured to bias the optical waveguide element against the housing to force the sealing surface of the waveguide element to mate with the face of the housing.7. The assembly of claim 6 , wherein the face comprises a concave frustoconical section and wherein the sealing surface comprises a complementary convex frustoconical section.8. The assembly of claim 7 , wherein the housing includes an opposing concave frustoconical section that is spaced from and oriented opposite the concave frustoconical section claim 7 , and the waveguide element comprises a complementary opposing convex frustoconical section for mating with the opposing concave frustoconical section.9. The assembly of claim 6 , wherein the optical waveguide element comprises a large diameter waveguide having a center plug portion and a pair of concentric tail sections ...

Variable area nozzle for gas turbine engines driven by shape memory alloy actuators

A gas turbine engine includes a variable area nozzle having a plurality of flaps. The flaps are actuated by a plurality of actuating mechanisms driven by shape memory alloy (SMA) actuators to vary fan exist nozzle area. The SMA actuator has a deformed shape in its martensitic state and a parent shape in its austenitic state. The SMA actuator is heated to transform from martensitic state to austenitic state generating a force output to actuate the flaps. The variable area nozzle also includes a plurality of return mechanisms deforming the SMA actuator when the SMA actuator is in its martensitic state.

Embedded optical sensor capable of strain and temperature measurement using a single diffraction grating

Optical sensor device having creep-resistant optical fiber attachments

A method and device for pressure sensing using an optical fiber having a core, a cladding and a Bragg grating imparted in the core for at least partially reflecting an optical signal at a characteristic wavelength. The cladding has two variation regions located on opposite sides of the Bragg grating to allow attachment mechanisms to be disposed against the optical fiber. The attachment mechanisms are mounted to a pressure sensitive structure so as to allow the characteristic wavelength to change according to pressure in an environment. In particular, the variation region has a diameter different from the cladding diameter, and the attachment mechanism comprises a ferrule including a front portion having a profile substantially corresponding to at least a portion of the diameter of the variation region and a butting mechanism which holds the ferrule against the optical fiber.

VOLTAGE INSULATED TEMPERATURE SENSOR WITH BRAGG GRILLE

Multiplexed Bragg grating sensors

A measurement system for fiber sensors includes a broadband light source 11 providing continuous light which is launched into a fiber 20 having a plurality (or string) of Bragg grating sensors 24, 28, 34. Each sensor has a predetermined central reflection wavelength which shifts as a function of applied strain. Reflected light 40 from the sensors 24, 28, 34 are fed to a plurality of optical bandbass filters 50, 64, 78, each having a monotonic region in a passband corresponding to one of the sensors. Each monotonic region transmits the reflected wavelength from a corresponding sensor. Light 52, 66, 80 is passed from the filters 50, 64, 78 to optical detectors 54, 68, 82 each providing an electrical signal having a magnitude related to transmission of the filter at the reflection wavelength of the sensor. Optional demodulators 58, 72, 86 are connected to each of the detectors 54, 68, 82 if the light source 10 is modulated. Such modulation provides noise immunity and allows demultiplexing of several strings of sensors.

Small profile pressure and temperature gauges

An optical assembly comprises an inner housing 804 disposed within an outer housing 802 and a large diameter optical waveguide 808 disposed within the inner housing. The waveguide has first and second portions 810, 814 with first and second gratings 812, 816. A port 806 communicates between the inner housing and a volume external to the outer housing. The optical waveguide has a diameter of at least 300 micrometres, and may include gold coated glass tubing. The waveguide may have a third portion and be dog bone shaped, with frustoconical ends for mating with seats in the inner housing. The waveguide may be a monolithic glass assembly. A further part of the disclosure has the assembly comprising: a divider for separating a first volume from a second volume; and a compressible element disposed in the first volume, wherein a first end of the element is coupled to the divider and a second end is sealed. In another part of the disclosure, a portion of the wall of the housing comprises a flexible member and the compressible element is a frame assembly wherein a first end is coupled to the flexible member and a second end is coupled to an inner surface of the housing, and the waveguide is held by the frame.

Highly sensitive accelerometer

A highly sensitive accelerometer for determining the acceleration of a structure includes a mass within a housing suspended by opposing support members. The support members are alternately wound around a pair of fixed mandrels and the mass in a push pull arrangement. At least a portion of one of the support members comprises a transducer capable measuring the displacement of the mass within the housing. An embodiment of the invention employs optical fiber coils as the support members for use in interferometric sensing processes. Arrays of such interferometer based accelerometers may be multiplexed using known techniques.

Small profile pressure and temperature gauges

Optical waveguide feedthrough assembly

An optical fiber feedthrough assembly includes a glass plug disposed in a recess of a feedthrough housing. The glass plug may define a large-diameter, cane-based, waveguide sealed within the recess in the housing and providing optical communication through the housing. Sealing occurs with respect to the housing at or around the glass plug of an optical waveguide element passing through the housing by braze sealing to the glass plug and/or embedding the glass plug in a polymer bonded with the plug to form a molded body that is sealed in the housing by, for example, compression mounting of the molded body or providing a sealing element around the molded body.

Pressure transducer with optical waveguide feedthrough assembly

Optical sensors used in harsh environments require a sealed pressure tight passage of an optical waveguide into an interior of the sensor. In one embodiment, a pressure sensor assembly for determining the pressure of a fluid in a harsh environment includes a sensing element suspended within a fluid filled housing. An optical waveguide that provides communication with the sensing element couples to a feedthrough assembly, which includes a cane-based optical waveguide forming a glass plug sealingly disposed in the housing. The glass plug provides optical communication between the optical waveguide and the sensing element. A pressure transmitting device can transmit the pressure of the fluid to the fluid within the housing. The assembly can maintain the sensing element in a near zero base strain condition and can protect the sensing element from shock/vibration.

Optical waveguide feedthrough assembly

An optical waveguide feedthrough assembly passes at least one optical waveguide through a bulk head, a sensor wall, or other feedthrough member. The optical waveguide feedthrough assembly comprises a cane-based optical waveguide that forms a glass plug sealingly disposed in a feedthrough housing. For some embodiments, the optical waveguide includes a tapered surface biased against a seal seat formed in the housing. The feedthrough assembly can include an annular gold gasket member disposed between the tapered surface and the seal seat. The feedthrough assembly can further include a backup seal. The backup seal comprises an elastomeric annular member disposed between the glass plug and the housing. The backup seal may be energized by a fluid pressure in the housing. The feedthrough assembly is operable in high temperature and high pressure environments.

Highly sensitive accelerometer

A highly sensitive accelerometer for determining the acceleration of a structure includes a mass within a housing suspended by opposing support members. The support members are alternately wound around a pair of fixed mandrels and the mass in a push pull arrangement. At least a portion of one of the support members comprises a transducer capable measuring the displacement of the mass within the housing. An embodiment of the invention employs optical fiber coils as the support members for use in interferometric sensing processes. Arrays of such interferometer based accelerometers may be multiplexed using known techniques.

Method and apparatus for recoating a fiber optic splice

A fiber optic splice recoat includes a flexible outer sleeve positioned over the splice area filled with a UV curable recoat material. The flexible outer sleeve is positioned over one of a pair of optical fibers to be spliced together. The glass fibers of the cables are spliced and the sleeve is positioned over the spliced area. The sleeve is filed with a UV curable reco at material and is subjected to UV energy to cure the recoat material. A fixtur e is provided for supporting the cables during the splice and recoat operation s. The fixture is further provided with a handle to keep the positioning blocks spaced at a predetermined distance.

Optical waveguide feedthrough assembly

An optical fiber feedthrough assembly includes a glass plug disposed in a recess of a feedthrough housing. The glass plug may define a large-diameter, cane-based, waveguide sealed within the recess in the housing and providing optical communication through the housing. Sealing occurs with respect to the housing at or around the glass plug of an optical waveguide element passing through the housing by braze sealing to the glass plug and/or embedding the glass plug in a polymer bonded with the plug to form a molded body that is sealed in the housing by, for example, compression mounting of the molded body or providing a sealing element around the molded body.

Optical fiber feedthrough using axial seals for bi-directional sealing

An optical waveguide feedthrough assembly passes at least one optical waveguide through a bulk head, a sensor wall, or other feedthrough member. The optical waveguide feedthrough assembly comprises a cane-based optical waveguide that forms a glass plug sealingly disposed in a feedthrough housing. A seal fills an annular space between the glass plug and the housing. The seal may be energized by a fluid pressure in the housing to establish sealing engagement. Further, the seal may provide bidirectional sealing. The feedthrough assembly is operable in high temperature and high pressure environments.

Optical pressure sensor device having creep-resistant optical fiber attachments

A method and device for pressure sensing using an optical fiber having a core, a cladding and a Bragg grating imparted in the core for at least partially reflecting an optical signal at a characteristic wavelength. The cladding has two variation regions located on opposite sides of the Bragg grating to allow attachment mechanisms to be disposed against the optical fiber. The attachment mechanisms are mounted to a pressure sensitive structure so as to allow the characteristic wavelength to change according to pressure in an environment. In particular, the variation region has a diameter different from the cladding diameter, and the attachment mechanism comprises a ferrule including a front portion having a profile substantially corresponding to at least a portion of the diameter of the variation region and a butting mechanism which holds the ferrule against the optical fiber.

Fiber optic cable for distributed acoustic sensing with increased acoustic sensitivity

Methods and apparatus for performing Distributed Acoustic Sensing (DAS) using fiber optics with increased acoustic sensitivity are provided. Acoustic sensing of a wellbore, pipeline, or other conduit/tube based on DAS may have increased acoustic sensitivity through fiber optic cable design and/or increasing the Rayleigh backscatter property of a fiber's optical core. Some embodiments may utilize a resonant sensor mechanism with a high Q coupled to the DAS device for increased acoustic sensitivity.

Creep-resistant optical fiber attachment

A creep-resistant optical fiber attachment includes an optical waveguide, such as an optical fiber, having a cladding and a core, having a variation region expanded or recessed) of an outer dimension of the waveguide and a structure, such as a ferrule, disposed against least a portion of the variation region. The fiber is held in tension against the ferrule and the ferrule has a size and shape that mechanically locks the ferrule to the variation, thereby holding the fiber in tension against the ferrule with minimal relative movement (or creep) in at least one direction between the fiber and the ferrule. The ferrule may be attached to or part of a larger structure, such as a housing. The variation and the ferrule may have various different shapes and sizes. There may also be a buffer layer between the cladding and the ferrule to protect the fiber and/or to help secure the ferrule to the fiber to minimize creep.

Multifunctional optical device having a spatial light modulator with an array of micromirrors

Highly sensitive optical fiber cavity coating removal detection

A highly sensitive optical fiber cavity coating removal detector employs an optical fiber 18 having a pair of Bragg gratings 20,30 embedded therein and separated by a section of fiber making up an optical cavity 26. The optical path length of the cavity 26 is sized with the central reflection wavelength of the fiber gratings 20,30 so as to create an optical resonator. The cavity 26 is coated with a material 40 which corrodes or is otherwise removable, such as aluminum. The coating 40 exerts forces 46 radially inward on the cavity 26 so as to cause the refractive index of the cavity and thus its optical path length to change, thereby causing the resonator to come out of resonance. The forces 46 on the cavity 26 are reduced when the coating 40 corrodes, thereby causing the resonator to re-enter resonance. Additionally, the coating causes optical losses to exist due to non-uniform variations in refractive index caused by non-uniform forces from coating irregularities.

Bragg grating pressure sensor

A fiber grating pressure sensor includes an optical sensing element 20,600 which includes an optical fiber 10 having a Bragg grating 12 impressed therein which is encased within and fused to at least a portion of a glass capillary tube 20 and/or a large diameter waveguide grating 600 having a core and a wide cladding and which has an outer transverse dimension of at least 0.3 mm. Light 14 is incident on the grating 12 and light 16 is reflected from the grating 12 at a reflection wavelength.lambda.1. The sensing element 20,600 may be used by itself as a sensor or located within a housing 48,60,90,270,300. When external pressure P increases, the grating 12 is compressed and the reflection wavelength .lambda.1 changes. The shape of the sensing element 20,600 may have other geometries, e.g., a"dogbone" shape, so as to enhance the sensitivity of shift in .lambda.1 due to applied external pressure and may be fused to an outer shell 50. At least a portion of the sensing element may be doped between a pair of gratings 150,152, to form a compression-tuned laser or the grating 12 or gratings 150,152 may be constructed as a tunable DFB laser. Also, the axial ends of element 20,600 where the fiber 10 exits the tube 20 may have an inner tapered region and/or a protruding tapered (or fluted) axial section 27 to provide strain relief or improved pull strength for the fiber 10. A temperature grating 270 may be used to measure temperature and allow for a temperature-corrected pressure measurement. The sensor may be suspended within an outer housing 112, by a fluid, spacers, or other means. The invention may also be used as a force transducer.

Bragg grating pressure sensor

A fiber grating pressure sensor includes an optical sensing element 20,600 which includes an optical fiber 10 having a Bragg grating 12 impressed therein which is encased within and fused to at least a portion of a glass capillary tube 20 and/or a large diameter waveguide grating 600 having a core and a wide cladding and which has an outer transverse dimension of at least 0.3 mm. Light 14 is incident on the grating 12 and light 16 is reflected from the grating 12 at a reflection wavelength.lambda.1. The sensing element 20,600 may be used by itself as a sensor or located within a housing 48,60,90,270,300. When external pressure P increases, the grating 12 is compressed and the reflection wavelength .lambda.1 changes. The shape of the sensing element 20,600 may have other geometries, e.g., a"dogbone" shape, so as to enhance the sensitivity of shift in .lambda.1 due to applied external pressure and may be fused to an outer shell 50. At least a portion of the sensing element may be doped between a pair of gratings 150,152, to form a compression-tuned laser or the grating 12 or gratings 150,152 may be constructed as a tunable DFB laser. Also, the axial ends of element 20,600 where the fiber 10 exits the tube 20 may have an inner tapered region 22 and/or a protruding tapered (or fluted) axial section 27 to provide strain relief or improved pull strength for the fiber 10. A temperature grating 270 may be used to measure temperature and allow for a temperature-corrected pressure measurement. The sensor may be suspended within an outer housing 112, by a fluid, spacers, or other means. The invention may also be used as a force transducer.

Bragg grating pressure sensor

A fiber grating pressure sensor includes an optical sensing element (20, 600) which includes an optical fiber (10) having a Bragg grating (12) impressed therein which is encased within and fused to at least a portion of a glass capillary tube (20) and/or a large diameter waveguide grating (600) having a core and a wide cladding and which has an outer transverse dimension of at least 0.3 mm. Light (14) is incident on the grating (12) and light (16) is reflected from the grating (12) at a reflection wavelength μ1. The sensing element (20, 600) may be used by itself as a sensor or located within a housing (48, 60, 90, 270, 300). When external pressure P increases, the grating (12) is compressed and the reflection wavelength μ1 changes.

Optical transducer with integrated feedthrough

Bourdon tube pressure gauge with integral optical strain sensors for measuring tension or compressive strain

Optical transducer with integrated feedthrough

OPTICAL TRANSDUCER WITH INTEGRATED FEEDTHROUGH A feedthrough assembly, comprising: at least one conductive line; and a feedthrough element(105) configured to isolate a first portion (110) of the feedthrough assembly from a second portion (120) of the assembly, wherein the feedthrough element (105) comprises: a housing (202) having a bore extending therethrough; a first seal (203) formed by a first portion of the at least one conductive line in contact with a mating surface of the bore of the housing (202); and a second seal (300) formed by contact between an arrangement of sealing elements with a second portion of the at least one conductive line and an inner surface of the housing (202).

Fiber optic cable for distributed acoustic sensing with increased acoustic sensitivity

Methods and apparatus for performing Distributed Acoustic Sensing (DAS) using fiber optics with increased acoustic sensitivity are provided. Acoustic sensing of a wellbore, pipeline, or other conduit/tube based on DAS may have increased acoustic sensitivity through fiber optic cable design and/or increasing the Rayleigh backscatter property of a fiber's optical core. Some embodiments may utilize a resonant sensor mechanism with a high Q coupled to the DAS device for increased acoustic sensitivity.

Highly sensitive accelerometer

A highly sensitive accelerometer for determining the acceleration of a structure includes a mass within a housing suspended by opposing support members. The support members are alternately wound around a pair of fixed mandrels and the mass in a push pull arrangement. At least a portion of one of the support members comprises a transducer capable of measuring the displacement of the mass within the housing. An embodiment of the invention employs optical fiber coils as support members for use in interferometric sensing processes. Arrays of such interferometer based accelerometers may be multiplexed using WDM or similar methods.

Reconfigurable optical add/drop multiplexer having an array of micro-mirrors

A reconfigurable optical add/drop multiplexer (ROADM) selectively drops and/or adds desired optical channel(s) from and/or to an optical WDM input signal. The ROADM includes a spatial light modulator having a micro-mirror device with an array of micro-mirrors, and a light dispersion element. The micro-mirrors tilt between two positions in response to a control signal provided by a controller in accordance with a switching algorithm and input command. 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 micro-mirrors of the micro-mirror device, which effectively pixelates the optical channels. To drop and/or add an optical channel to the optical input signal, mirrors associated with each desired optical channel are tilted away from a return path to the second position.

Optical filter device having creep-resistant optical fiber attachments

A method and device for tuning an optical device including an optical fiber having a core, a cladding and a Bragg grating imparted in the core to partially reflect an optical signal at a reflection wavelength characteristic of the spacing of the Bragg grating. The cladding has two variation regions located on opposite sides of the Bragg grating to allow attachment mechanisms to be disposed against the optical fiber. The attachment mechanisms are mounted to a frame so as to allow the spacing of the Bragg grating to be changed by an actuator which tunes the reflection wavelength. In particular, the variation region has a diameter different from the cladding diameter, and the attachment mechanism comprises a ferrule including a front portion having a profile substantially corresponding to diameter of the variation region and a butting mechanism butting the ferrule against the optical fiber.

Embedded optical sensor for measuring voltage and temperature with a single diffraction grating

Optical fiber feedthrough using axial seals for bi-directional sealing

An optical waveguide feedthrough assembly passes at least one optical waveguide through a bulk head, a sensor wall, or other feedthrough member. The optical waveguide feedthrough assembly comprises a cane-based optical waveguide that forms a glass plug sealingly disposed in a feedthrough housing. A seal fills an annular space between the glass plug and the housing. The seal may be energized by a fluid pressure in the housing to establish sealing engagement. Further, the seal may provide bidirectional sealing. The feedthrough assembly is operable in high temperature and high pressure environments.

Array temperature sensing method and system

Methods and apparatus enable monitoring conditions in a well-bore using multiple cane-based sensors. The apparatus includes an array of cane-based Bragg grating sensors located in a single conduit for use in the well-bore. For some embodiments, each sensor is located at a different linear location along the conduit allowing for increased monitoring locations along the conduit.

Method and device for providing stable and precise optical reference signals

A device for providing optical reference signals includes an optical fiber having a reference array formed therein, the array including at least one reference fiber Bragg grating. The array is mounted on a mounting fixture having a low coefficient of thermal expansion. The mounting fixture is in thermal contact with a thermoelectric (TE) element, and a controller controls the temperature of the TE element. A temperature sensor is in thermal contact with the mounting fixture and provides feedback to the controller to control to the temperature of the TE element to thereby maintain the temperature of the mounting fixture at a selected temperature. The other side of the temperature control element is mounting to a heat sink element. The optical fiber is attached to the mounting fixture in a configuration that minimizes any stress or strain in the optical fiber. The array includes a plurality of reference fiber Bragg gratings, and each grating is positioned in the same location on the surface of the mounting fixture. The device may be positioned in an insulating package to further enhance the temperature stability of the mounting fixture and to minimize any temperature variations or gradients in the mounting fixture.

Acoustically enhanced optical cables

Resistant optical fiber fastener

Fiber optic cable for distributed acoustic sensing with increased acoustic sensitivity

Methods and apparatus for performing Distributed Acoustic Sensing (DAS) using fiber optics with increased acoustic sensitivity are provided. Acoustic sensing of a wellbore, pipeline, or other conduit/tube based on DAS may have increased acoustic sensitivity through fiber optic cable design and/or increasing the Rayleigh backscatter property of a fiber's optical core. Some embodiments may utilize a resonant sensor mechanism with a high Q coupled to the DAS device for increased acoustic sensitivity.

Forward scattering laser particulate sensor

Abstract Forward Scattering Laser Particulate Sensor A sensor employs a laser to obtain a colli-mated light beam for transmission across the gas effluent of a catalytic cracking process. Parti-culate matter entrained in the gas flow forward scatters light energy to a collecting aperture which, in turn focuses the scattered light on a first photodetector. A second photodetector receives directly transmitted light energy. A ratio between the output signals of the two photodetectors is derived and presented to a threshold level detector. If the magnitude of the scatter exceeds a predetermined level it is concluded that a catalyst load dump has occurred. The optical system is carefully selected to ensure that only light energy scattered from a sample volume within the entrained gas flow reaches the first photodetector. This is im-portant because it prevents particulate matter on the surfaces of the transparent windows from affecting the operating of the sensor.

Method and apparatus for measuring a parameter of a high temperature fluid flowing within a pipe using an array of piezoelectric based flow sensors

A method, apparatus and system are provided to measure the process flow of a fluid or medium traveling in a pipe. The system and apparatus feature a standoff and piezoelectric-based sensor arrangement having a plurality of standoffs arranged on a pipe and a plurality of sensor bands, each arranged on a respective plurality of standoffs, each having at least one sensor made of piezoelectric material arranged thereon to detect unsteady pressure disturbances in the process flow in the pipe which in turn can be converted to the velocity of and/or speed of sound propagating within the pipe, and a cooling tube arranged in relation to the plurality of standoffs for actively cooling the sensor band; and further comprise a processing module for converting one or more sensor signals into a measurement containing information about the flow of the fluid or medium traveling in the pipe, as well as a pump and heat exchanger for processing the cooling fluid flowing through the cooling tube. The processing includes maintaining the cooling fluid at a desired operating temperature.

Optical transducer with integrated feedthrough

An optical transducer is provided. A "measuring" portion of the transducer may be exposed to a high pressure and fluids when the optical transducer is deployed (e.g., in a wellbore or other industrial setting). The transducer may include an optical waveguide with a first portion that forms a first seal that isolates an "instrumentation" portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed. The transducer may also include a second seal with a "stack" of material elements that contact a second portion of the optical waveguide to also isolate the instrumentation portion of the transducer from exposure to the high pressure and fluids to which the measuring portion may be exposed.

Array temperature sensing method and system

Array Temperature Sensing (ATS) enables monitoring temperatures along a length of a well by placing sensors at desired locations along a waveguide disposed in the well. A challenge to using an ATS system involves the packaging of the sensors such that they are responsive to the temperature of their surroundings, but are free from, or insensitive to, strain changes over their lifetime. Methods and apparatus provided herein enable monitoring conditions in a well-bore using multiple cane-based sensors, such that they are responsive to the temperature of their surroundings. The apparatus includes a plurality of sensors disposed along a length of an optical waveguide and a conduit surrounding and spanning the length of the waveguide, wherein the sensors are disposed within enlarged outer diameter portions of the waveguide relative to an interconnecting portion of the waveguide between the sensors.

Optical channel monitor having an array of micro-mirrors

A reconfigurable optical channel monitor selects and determines a parameter of desired optical channel(s) from and/or to an optical WDM input signal. The OCM 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 response to a control signal from a controller in accordance with a switching algorithm and an input command. A collimator, diffraction grating, and Fourier lens collectively converge the optical input channels onto the micro-mirrors array. The optical channel is focused onto a plurality of micro-mirrors. To select each input channel, a group of micro-mirrors associated with each desired input channel is tilted to reflect the desired input channel back along the return path to a photodetector and processing unit to determine a parameter of the selected input signal.

Optical channel monitor having an array of micro-mirrors

A reconfigurable optical channel monitor selects and determines a parameter of desired optical channel(s) from and/or to an optical WDM input signal. The OCM 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 response to a control signal from a controller in accordance with a switching algorithm and an input command. A collimator, diffraction grating, and Fourier lens collectively converge the optical input channels onto the micro-mirrors array. The optical channel is focused onto a plurality of micro-mirrors. To select each input channel, a group of micro-mirrors associated with each desired input channel is tilted to reflect the desired input channel back along the return path to a photodetector and processing unit to determine a parameter of the selected input signal.

Sveiset strekkbasert fibergitter trykksensor

Fused tension-based fiber grating pressure sensor

Sammensmeltet strekkbasert fibergitter trykksensor