Abstract: A system comprises an optical fiber, a manipulator assembly, and a control unit. The manipulator assembly comprises a chassis, an optical fiber cleaning assembly housed within the chassis, and a drive mechanism housed within the chassis. The optical fiber cleaning assembly comprises a cleaning tape, a first spool on which the cleaning tape is wound, and a second spool onto which the cleaning tape is drawn after use. The drive mechanism is configured to advance the cleaning tape from the first spool to the second spool such that a portion of the cleaning tape wipes a face of the optical fiber. The control unit is configured to control the drive mechanism to advance the cleaning tape.

Abstract: An optical assembly can include a pedestal attached to a substrate and a first optical component laser welded to the pedestal. In some examples, a. bond between the first optical component and the pedestal can be formed from material of at least one of the first optical component and the pedestal melted via later welding. In some examples, the first optical component can be positioned to receive light from a second optical component, attached with the substrate, or transmit light to the second optical component. In some examples, a pedestal can include a first pedestal surface that is attached to the substrate and a second pedestal surface, angled with respect to the first pedestal surface, that is attached to an optical component. In some examples, a pedestal can include a first pedestal element attached to a second pedestal element, such as by laser welding.

Abstract: Example embodiments include an optical assembly for an optical interrogation system having a single core or a multicore sensing fiber, a measurement fiber to couple light into the sensing fiber, and a reference fiber arranged with the measurement fiber as part of an optical interferometer. A beam splitter combines light from the sensing fiber and with light from the reference fiber. A polarization beam splitting prism separates the combined light into first polarized light and second polarized light that is orthogonal to the first polarized light. The optical assembly can substantially reduce the size, complexity, or cost associated with the traditional optical components in an optical interrogation system that it replaces. Other example optical assemblies are described. Embodiments describe optical interrogation systems using the example optical assemblies.

Abstract: A fiber includes M primary cores and N redundant cores, where M an integer is greater than two and N is an integer greater than one. Interferometric circuitry detects interferometric pattern data associated with the M primary cores and the N redundant cores when the optical fiber is placed into a sensing position. Data processing circuitry calculates a primary core fiber bend value for the M primary cores and a redundant core fiber bend value for the N redundant cores based on a predetermined geometry of the M primary cores and the N redundant cores in the fiber and detected interferometric pattern data associated with the M primary cores and the N redundant cores. The primary core fiber bend value and the redundant core fiber bend value are compared in a comparison. The detected data for the M primary cores is determined reliable or unreliable based on the comparison. A signal is generated in response to an unreliable determination.

Abstract: An optical fiber includes multiple optical cores configured in the fiber including a set of primary cores and an auxiliary core. An interferometric measurement system uses measurements from the multiple primary cores to predict a response from the auxiliary core. The predicted auxiliary core response is compared with the actual auxiliary core response to determine if they differ by more than a predetermined amount, in which case the measurements from the multiple primary cores may be deemed unreliable.

Abstract: A system can direct light into an optical fiber. Imaging optics can form an image of an end of an optical fiber. An actuatable optical element can be configured to define an optical path that extends to the actuatable optical element and further extends to the end of the optical fiber. A processor can determine a location in the image of a specified feature in the image. The processor can cause, based on the location of the specified feature in the image, the actuatable optical element to actuate to align the optical path to a core of the optical fiber. A light source can direct a light beam along the optical path to couple into the core of the optical fiber.

Abstract: Example embodiments add an optical amplifier to a multi-channel, continuously swept OFDR measurement system, adjust amplified swept laser output power between rising and falling laser sweeps, and/or utilize portions of a laser sweep in which OFDR measurements are not typically performed to enhance the integrity of the OFDR measurement system, improve the performance and quality of OFDR measurements, and perform additional measurements and tests.

Abstract: A fiber includes M primary cores and N redundant cores, where M an integer is greater than two and N is an integer greater than one. Interferometric circuitry detects interferometric pattern data associated with the M primary cores and the N redundant cores when the optical fiber is placed into a sensing position. Data processing circuitry calculates a primary core fiber bend value for the M primary cores and a redundant core fiber bend value for the N redundant cores based on a predetermined geometry of the M primary cores and the N redundant cores in the fiber and detected interferometric pattern data associated with the M primary cores and the N redundant cores. The primary core fiber bend value and the redundant core fiber bend value are compared in a comparison. The detected data for the M primary cores is determined reliable or unreliable based on the comparison. A signal is generated in response to an unreliable determination.

Abstract: An optical fiber includes multiple optical cores configured in the fiber including a set of primary cores and an auxiliary core. An interferometric measurement system uses measurements from the multiple primary cores to predict a response from the auxiliary core. The predicted auxiliary core response is compared with the actual auxiliary core response to determine if they differ by more than a predetermined amount, in which case the measurements from the multiple primary cores may be deemed unreliable.

Abstract: A system can direct light into an optical fiber. Imaging optics can form an image of an end of an optical fiber. An actuatable optical element can be configured to define an optical path that extends to the actuatable optical element and further extends to the end of the optical fiber. A processor can determine a location in the image of a specified feature in the image. The processor can cause, based on the location of the specified feature in the image, the actuatable optical element to actuate to align the optical path to a core of the optical fiber. A light source can direct a light beam along the optical path to couple into the core of the optical fiber.

Abstract: Example embodiments add an optical amplifier to a multi-channel, continuously swept OFDR measurement system, adjust amplified swept laser output power between rising and falling laser sweeps, and/or utilize portions of a laser sweep in which OFDR measurements are not typically performed to enhance the integrity of the OFDR measurement system, improve the performance and quality of OFDR measurements, and perform additional measurements and tests.

Abstract: An optical fiber with one or more microgratings is disclosed. Methods and apparatus are described for making an optical fiber with one or more microgratings. Methods and apparatus are described for an optical fiber with one or more microgratings. Optical sensing methods and an optical sensing system effectively decouple strain range from the laser tuning range, permit the use of a smaller tuning range without sacrificing strain range, and compensate for ambiguity in phase measurements normally associated with smaller tuning ranges.

Abstract: A system for distributed heat flux sensing of body tissue includes a distributed sensor, a thermal energy source, and one or more processors. The distributed sensor provides a plurality of temperature measurements corresponding to a plurality of points in a measurement range. The thermal energy source applies thermal energy to the body tissue along the measurement range. The one or more processors are configured to receive the plurality of temperature measurements from the distributed sensor, determine an amount of thermal energy applied by the thermal energy source at each of the plurality of points, and determine heat flux at each of the plurality of points based on the plurality of temperature measurements and the amount of thermal energy applied by the thermal energy source. The plurality of temperature measurements correspond to the plurality of points.

Abstract: An optical fiber with one or more microgratings is disclosed. Methods and apparatus are described for making an optical fiber with one or more microgratings. Methods and apparatus are described for an optical fiber with one or more microgratings. Optical sensing methods and an optical sensing system effectively decouple strain range from the laser tuning range, permit the use of a smaller tuning range without sacrificing strain range, and compensate for ambiguity in phase measurements normally associated with smaller tuning ranges.

Abstract: To sense the shape of a multicore optical fiber sensor, light reflected in a center and two or more helixed outer cores of the optical fiber sensor is measured, and phases associated with strain in the center and helixed outer cores is tracked along the length of the fiber sensor. Further, a wobble signal indicative of a variation in the spin rate of the fiber sensor is determined. Based on the tracked phases and the wobble signal, the fiber shape is computed.

Abstract: Described are optical fibers, e.g., for use in stress-sensing or shape-sensing applications, that use overlapping grating configurations with chirped gratings to facilitate strain delay registration. In accordance with various embodiments, a fiber core may, for instance, have two overlapping sets of chirped gratings that differ in the direction of the chirp between the first and second sets, or a set of chirped gratings overlapping with a single-frequency grating. Also described are strain sensing systems and associated computational methods employing optical fibers with overlapping gratings.

Abstract: A system for distributed heat flux sensing of body tissue includes a distributed sensor, a thermal energy source, and one or more processors. The distributed sensor provides a plurality of temperature measurements corresponding to a plurality of points in a measurement range. The thermal energy source applies thermal energy to the body tissue along the measurement range. The one or more processors are configured to receive the plurality of temperature measurements from the distributed sensor, determine an amount of thermal energy applied by the thermal energy source at each of the plurality of points, and determine heat flux at each of the plurality of points based on the plurality of temperature measurements and the amount of thermal energy applied by the thermal energy source. The plurality of temperature measurements correspond to the plurality of points.

Abstract: Example embodiments include an optical interrogation system with a sensing fiber having a single core, the single core having multiple light propagating modes. Interferometric apparatus probes the single core multimode sensing fiber over a range of predetermined wavelengths and detects measurement interferometric data associated with the multiple light propagating modes of the single core for each predetermined wavelength in the range. Data processing circuitry processes the measurement interferometric data associated with the multiple light propagating modes of the single core to determine one or more shape-sensing parameters of the sensing fiber from which the shape of the fiber in three dimensions can be determined.

Abstract: A system comprises an optical fiber, a manipulator assembly, and a control unit. The manipulator assembly comprises a chassis, an optical fiber cleaning assembly housed within the chassis, and a drive mechanism housed within the chassis. The optical fiber cleaning assembly comprises a cleaning tape, a first spool on which the cleaning tape is wound, and a second spool onto which the cleaning tape is drawn after use. The drive mechanism is configured to advance the cleaning tape from the first spool to the second spool such that a portion of the cleaning tape wipes a face of the optical fiber. The control unit is configured to control the drive mechanism to advance the cleaning tape.

Abstract: Example embodiments include an optical interrogation system with a sensing fiber having a single core, the single core having multiple light propagating modes. Interferometric apparatus probes the single core multimode sensing fiber over a range of predetermined wavelengths and detects measurement interferometric data associated with the multiple light propagating modes of the single core for each predetermined wavelength in the range. Data processing circuitry processes the measurement interferometric data associated with the multiple light propagating modes of the single core to determine one or more shape-sensing parameters of the sensing fiber from which the shape of the fiber in three dimensions can be determined.