Patent application number | Description | Published |
20080273849 | SINGLE MODE OPTICAL FIBER WITH IMPROVED BEND PERFORMANCE - Methods and apparatus relate to optical fibers suitable for use in sensing applications exposed to radiation environments. The fibers include a core of pure silica or chlorine doped silica surrounded by a fluorinated silica cladding. These glasses for the core and cladding utilize dopants that resist radiation-induced attenuation. A two step process for forming the cladding can achieve necessary concentrations of the fluorine by performing a soot deposition process in a different environment from a consolidation process where the soot is sintered into a glass. Concentration of fluorine doped into the cladding layer enables obtaining a numerical aperture that confines a mono-mode of the fiber to resist bend-induced attenuation. Dimensions of the fiber further facilitate bending ability of the fiber. | 11-06-2008 |
20080317420 | LARGE DIAMETER OPTICAL WAVEGUIDE, GRATING AND LASER - A large diameter optical waveguide, grating, and laser includes a waveguide having at least one core surrounded by a cladding, the core propagating light in substantially a few transverse spatial modes; and having an outer waveguide dimension of said waveguide being greater than about 0.3 mm. At least one Bragg grating may be impressed in the waveguide. The waveguide may be axially compressed which causes the length of the waveguide to decrease without buckling. The waveguide may be used for any application where a waveguide needs to be compression tuned. Also, the waveguide exhibits lower mode coupling from the core to the cladding and allows for higher optical power to be used when writing gratings without damaging the waveguide. The waveguide may resemble a short “block” or a longer “cane” type, depending on the application and dimensions used. | 12-25-2008 |
20090079989 | OPTICAL FIBER COATING SYSTEM AND MONITORING METHOD FOR IMPROVED THERMAL PERFORMANCE IN FIBER OPTIC SENSORS - A method and apparatus for reducing the thermal induced errors in an IFOG system. The apparatus including a highly thermally conductive material configured to encapsulate a waveguide of an interferometric fiber optic gyroscope (IFOG). The highly thermally conductive material more evenly distributes thermal changes encountered by a sensing coil of the IFOG thereby substantially reducing errors in the IFOG system. | 03-26-2009 |
20090310925 | PURE SILICA CORE, HIGH BIREFRINGENCE, SINGLE POLARIZATION OPTICAL WAVEGUIDE - Methods and apparatus provide for birefringent waveguides suitable for optical systems exhibiting polarization dependence such as interferometer sensors including Sagnac interferometric fiber optic gyroscopes (IFOG). The waveguides, for some embodiments, may offer single polarization performance over lengths of about a kilometer or more due to polarization dependent attenuation. According to some embodiments, the waveguides incorporate a pure silica core for resistance to radiation-induced attenuation (RIA). | 12-17-2009 |
20110091175 | SINGLE MODE OPTICAL FIBER WITH IMPROVED BEND PERFORMANCE - Methods and apparatus relate to optical fibers suitable for use in sensing applications exposed to radiation environments. The fibers include a core of pure silica or chlorine doped silica surrounded by a fluorinated silica cladding. These glasses for the core and cladding utilize dopants that resist radiation-induced attenuation. A two step process for forming the cladding can achieve necessary concentrations of the fluorine by performing a soot deposition process in a different environment from a consolidation process where the soot is sintered into a glass. Concentration of fluorine doped into the cladding layer enables obtaining a numerical aperture that confines a mono-mode of the fiber to resist bend-induced attenuation. Dimensions of the fiber further facilitate bending ability of the fiber. | 04-21-2011 |
20120076452 | SENSING DEVICE HAVING A LARGE DIAMETER D-SHAPED OPTICAL WAVEGUIDE - An optical sensor formed from an optical waveguide having at least one core surrounded by a cladding and a large diameter generally D-shaped portion is disclosed. Axial or compressive strain across the D-shaped cross section may be determined by measuring the change in polarization or birefringence of the light output from the sensor. A layer responsive to a parameter may be disposed on a flat portion of the D-shaped portion of the sensor. The refractive index of the layer changes and/or the layer applies a strain on the sensor in response to the parameter. Changes in the refractive index of the layer alters the light output from the sensor, which is measured over time and correlated to the parameter. | 03-29-2012 |
20120082175 | LARGE DIAMETER OPTICAL WAVEGUIDE, GRATING AND LASER - A large diameter optical waveguide, grating, and laser includes a waveguide having at least one core surrounded by a cladding, the core propagating light in substantially a few transverse spatial modes; and having an outer waveguide dimension of said waveguide being greater than about 0.3 mm. At least one Bragg grating may be impressed in the waveguide. The waveguide may be axially compressed which causes the length of the waveguide to decrease without buckling. The waveguide may be used for any application where a waveguide needs to be compression tuned. Also, the waveguide exhibits lower mode coupling from the core to the cladding and allows for higher optical power to be used when writing gratings without damaging the waveguide. The waveguide may resemble a short “block” or a longer “cane” type, depending on the application and dimensions used. | 04-05-2012 |
20130167594 | POLARIZATION CONTROLLING OPTICAL FIBER PREFORM AND PREFORM FABRICATION METHODS - Methods to fabricate an optical preform for draw into Polarization Maintaining (PM) or Polarizing (PZ) optical fiber are provided. The methods involve assembly of pre-shaped and pieced together bulk glass elements into preforms (“assembled preforms”) for simultaneous fusing and drawing into optical fiber. These preforms form a stress-induced birefringent optical core when drawn to fiber. | 07-04-2013 |
Patent application number | Description | Published |
20080253428 | STRAIN AND HYDROGEN TOLERANT OPTICAL DISTRIBUTED TEMPERATURE SENSOR SYSTEM AND METHOD - A distributed temperature sensing system and method includes an optical sensing waveguide. The optical sensing waveguide is a single mode waveguide having a substantially pure silica core and a large outer diameter. The system further includes an optical instrument optically connected to the optical sensing waveguide. The optical instrument is configured for generating an optical excitation signal along the optical sensing waveguide, and is also configured for receiving a return optical signal indicative of the temperature at one or more locations along the optical sensing waveguide. | 10-16-2008 |
20090290147 | DYNAMIC POLARIZATION BASED FIBER OPTIC SENSOR - An optical fiber sensor system includes an optical fiber. A linear polarizing component is configured to communicate with the optical fiber. The linear polarizing component includes a polarization sensing fiber to be disposed adjacent to and preferably collinear with the optical fiber. A light source communicates with the linear polarizing component for generating a light signal along the optical fiber. A reflector is disposed along the optical fiber for reflecting back the light signal along the optical fiber. An optical detector communicates with the linear polarizing component. A signal processor communicating with the optical detector and configured for determining from the reflected light signal dynamic events along the optical fiber. | 11-26-2009 |
20090314102 | POLARIZATION BASED FIBER OPTIC DOWNHOLE FLOWMETER - A flow monitoring system includes a pipe for transporting a fluid therethrough. An optical fiber generally spirals about the pipe along a longitudinal portion having a predetermined length to serve as a single transducer for detecting flow information from the longitudinal portion. A linear polarizer/analyzer circuit communicates with the optical fiber. A light source communicates with the linear polarizer/analyzer circuit and generates a light signal along the optical fiber at a frequency greater than a period of a disturbance to flow past the predetermined length of the transducer. A reflector is disposed along the optical fiber for reflecting the light signal along the optical fiber. An optical detector communicates with the linear polarizer/analyzer circuit. The optical detector determines from the light signal dynamic events along the optical fiber indicative of flow disturbances passing by the transducer. | 12-24-2009 |
20120039359 | LOW PROFILE, HIGH TEMPERATURE, HYDROGEN TOLERANT OPTICAL SENSING CABLE - A sensing cable has a sensing fiber assembly, which includes a pair of sensing fibers joined by a turnaround section with a modal filter, at a terminating end of the sensing fibers. The sensing cable also includes an inner sleeve that surrounds the sensing fiber assembly and an armored casing that caps the terminating end of the inner sleeve. The sensing cable has a low profile and its components are each made of high temperature and hydrogen tolerant materials and are capable of prolonged operation at high temperatures, such as up to 300° C., in hydrogen environments over long lengths of fiber. A distributed thermal sensing (DTS) interrogator is connected to the sensing cable and performs DTS measuring according to protocols and algorithms that leverage the modal filter of the turnaround section to calculate temperature readings along the sensing fiber assembly. | 02-16-2012 |
20120039360 | METHOD FOR PERFORMING OPTICAL DISTRIBUTED TEMPERATURE SENSING (DTS) MEASUREMENTS IN HYDROGEN ENVIRONMENTS - A method for calculating a temperature along a length of a sensing fiber of a distributed thermal sensing (DTS) system. The sensing fiber, which has two ends, is heat resistant for operation up to 300° C. The DTS system includes a two-channel DTS interrogator that is attached to each of the two ends of the sensing fiber. The DTS interrogator interrogates the sensing fiber from both ends, calculates a temperature difference between co-located positions along the length of the sensing fiber for each end, and determines an error associated with the temperature difference. Based on the determined error, a corrected temperature value along the length of the sensing fiber is calculated and outputted. | 02-16-2012 |
20120039561 | HIGH TEMPERATURE FIBER OPTIC TURNAROUND - A sensing cable includes a pair of sensing fibers that are connected to one another by a U-shaped turnaround section. The turnaround section is a section of sensing fiber coated with a jacket that includes metallic components. The turnaround section is bent and, then, annealed according to a method of the present invention. The turnaround section is robust and reduced in size (i.e., radius). The sensing cable also includes an inner sleeve that surrounds the sensing fibers and an elongated outer armor casing (i.e., including an armor tube and a sealing cap) that encases a terminating end thereof. The armor tube and the sealing cap protect the sensing fiber from mechanical and chemical harm, are reduced in size and facilitate insertion of the sensing cable into downhole environments. The sensing cable has improved operating range up to 300° C. | 02-16-2012 |
20140060199 | MULTI-MODE HOLOGRAPHIC PRESSURE SENSOR - A holographic pressure sensing apparatus includes a first optical fiber with a diffractive element at its end face, and a light-coupling component for receiving from the first optical fiber end face first and second images respectively formed by interaction with the diffractive element of a first light of a first wavelength and a second light of a second wavelength. Displacement of the light-coupling component, toward or away from the first optical fiber end face, will adjust an overlap of the first and second images, such that a change in a measurement of said overlap will indicate a change of the pressure in the fluid surrounding the casing. | 03-06-2014 |