Abstract: An intra-oral scanning device includes a light source and an optical system, and communicates with a display system. The device provides for more efficient transmission and capture of images. It integrates OCT scanning with RGB-based scanning. In operation, the device is used for recording topological characteristics of teeth, dental impressions, or stone models by digital methods and for use in CAD/CAM of dental restorative prosthetic devices. To that end, the RGB-based scan obtains surface data (e.g., a margin), while the OCT scan penetrates the surface. The two scanners operate from within the same physical housing and preferably at the same time such that only one scanning pass (to obtain all necessary data) is required. The 3D data obtained from the OCT scan is registered with the 3D data obtained from the RGB-based scan by virtue of being captured using a common return path.

Abstract: A downhole tool orientation determination system to determine a radial orientation of a tool conveyed downhole into a pipe via a carrier and a method of determining a radial orientation of a tool conveyed downhole into a pipe via a carrier are described. The system includes an orientation tool conveyed downhole by the carrier that conveys the tool, and a distributed acoustic sensor (DAS). The DAS includes an optical fiber disposed axially along an outer surface of the pipe; and a processor to determine an orientation of the orientation tool with respect to the optical fiber based on a measurement by the optical fiber at different rotational positions of the orientation tool. The processor determines the radial orientation of the tool with respect to the optical fiber based on the orientation of the orientation tool with respect to the optical fiber.

Abstract: A method for estimating an environmental parameter includes transmitting a first interrogation signal into an optical fiber, receiving a reflected return signal including light reflected from one or more of the plurality of FBG's in the fiber and receiving at a processor data describing the reflected return signal. The received data is comparted to expected data to determine a shift in wavelength of light reflected for one or more of the plurality of FBGs and a change in a length of a dead zone of the optical fiber based on the comparison is also determined. From this, estimates of locations two or more of the plurality of FBG's are formed.

Abstract: A method and system to perform distributed downhole acoustic sensing in a borehole are described. The system includes an optical fiber comprising at least one reflector, and a tunable laser configured to perform a transmission of a range of wavelengths through the optical fiber. The system also includes a receiver configured to receive an interferometer signal resulting from the transmission, and a processor configured to determine a component of the interferometer signal.

Abstract: A temperature sensing arrangement includes a member having a first coefficient of thermal expansion, and an optical fiber having a second coefficient of thermal expansion. The optical fiber is strain transmissively mounted to the member. And the first coefficient of thermal expansion is greater than the second coefficient of thermal expansion such that strain measurable in the optical fiber is correlatable to temperature changes in the member.

Abstract: A method for estimating a parameter includes: generating an optical signal, the optical signal modulated via a modulation signal; transmitting the modulated optical signal from a light source into an optical fiber, the optical fiber including a plurality of sensing locations disposed along the optical fiber and configured to reflect light; receiving a reflected signal including light reflected from the plurality of sensing locations; and combining, in parallel, each of a plurality of reference signals with the reflected signal to estimate a value of the parameter.

Abstract: Disclosed herein is a method for sensing one or more selected parameters related to a structure of interest, for example, the shape of an isolated structure. A cable is attached to the structure of interest at one or more attachment points. The cable contains one or more optical fibers. One or more light signals are transmitted into the one or more optical fibers and then detected to form a data set. The data set is compared with information known about the one or more attachment points to determine error values. The error values are then combined with the data set to determine the selected parameters associated with the structure.

Abstract: An apparatus for monitoring strain on a downhole component includes a fiber optic sensor having a length thereof in operable relationship with a downhole component and configured to deform in response to deformation of the downhole component. The fiber optic sensor defines a continuous, distributed sensor. An interrogation assembly is configured to transmit an electromagnetic interrogation signal into the fiber optic sensor and is configured to receive reflected signals therefrom. A processing unit is configured to receive information from the interrogation assembly and is configured to determine a strain on the downhole component during running of the downhole component to depth in a borehole.

Abstract: A method for estimating a parameter includes: transmitting a control signal to a coherent optical source, the control signal configured to chaotically vary an output of the optical source and generate a chaotically excited optical signal; transmitting the optical signal from the optical source into an optical fiber, the optical fiber including at least one sensing location; receiving a reflected signal including light reflected from the at least one sensing location; and estimating a value of the parameter using the reflected signal.

Abstract: An apparatus for estimating at least one parameter in a downhole environment includes: an optical fiber configured to be disposed in a borehole, the optical fiber having a property that causes intrinsic backscattering of signals transmitted therein. The property varies along a length of the optical fiber to generate a variable intensity of the backscattering, the intensity of backscattering varying along the optical fiber as a function of distance from an end of the optical fiber. The apparatus also includes a light source configured to send an optical signal into the optical fiber; and a detector configured to receive a return signal including backscattered signals.

Abstract: A downhole tool orientation determination system to determine a radial orientation of a tool conveyed downhole into a pipe via a carrier and a method of determining a radial orientation of a tool conveyed downhole into a pipe via a carrier are described. The system includes an orientation tool conveyed downhole by the carrier that conveys the tool, and a distributed acoustic sensor (DAS). The DAS includes an optical fiber disposed axially along an outer surface of the pipe; and a processor to determine an orientation of the orientation tool with respect to the optical fiber based on a measurement by the optical fiber at different rotational positions of the orientation tool. The processor determines the radial orientation of the tool with respect to the optical fiber based on the orientation of the orientation tool with respect to the optical fiber.

Abstract: A system and method to obtain and process interferometer output scans is described. The interferometer-based sensor system includes a tunable laser to transmit a transmit signal and a polarization scrambler to produce a polarization state change on the transmit signal. The system also includes an interferometer to provide an output scan based on the transmit signal with the polarization state change and a processor to process the output scan.

Abstract: Disclosed herein is a method for sensing one or more selected parameters related to a structure of interest, for example, the shape of an isolated structure. A cable is attached to the structure of interest at one or more attachment points. The cable contains one or more optical fibers. One or more light signals are transmitted into the one or more optical fibers and then detected to form a data set. The data set is compared with information known about the one or more attachment points to determine error values. The error values are then combined with the data set to determine the selected parameters associated with the structure.

Abstract: A method for estimating an environmental parameter includes transmitting a first interrogation signal into an optical fiber, receiving a reflected return signal including light reflected from one or more of the plurality of FBG's in the fiber and receiving at a processor data describing the reflected return signal. The received data is comparted to expected data to determine a shift in wavelength of light reflected for one or more of the plurality of FBGs and a change in a length of a dead zone of the optical fiber based on the comparison is also determined. From this, estimates of locations two or more of the plurality of FBG's are formed.

Abstract: An interferometer and a method of monitoring a downhole environment are described. The interferometer includes a coherent light source to emit pulses of light on a fiber, and a plurality of reflectors arranged on the fiber to reflect light from the coherent light source, each of the plurality of reflectors comprising broad band fiber Bragg gratings (FBGs), the fiber being rigidly disposed within a cable that is rigidly attached in the downhole environment. The interferometer also includes a processor to process a reflection signal resulting from the light reflected by two or more of the plurality of reflectors.

Abstract: A system and method to obtain acoustic information from a borehole penetrating the earth are described. The system includes a light source to provide a continuous output beam and a modulator to modulate the continuous output beam with a modulation signal to provide a frequency modulated continuous wave (FMCW) to be sent out on an optical fiber disposed along the borehole, the optical fiber including a plurality of reflectors at known locations along the optical fiber. The system also includes a processor to process a light reflection signal from the optical fiber to determine the acoustic information.

Abstract: An apparatus for estimating at least one parameter in a downhole environment includes: an optical fiber configured to be disposed in a borehole, the optical fiber having a property that causes intrinsic backscattering of signals transmitted therein. The property varies along a length of the optical fiber to generate a variable intensity of the backscattering, the intensity of backscattering varying along the optical fiber as a function of distance from an end of the optical fiber. The apparatus also includes a light source configured to send an optical signal into the optical fiber; and a detector configured to receive a return signal including backscattered signals.

Abstract: Disclosed herein is a system for measuring characteristics in a well bore. The system includes a fiber-optic wire extending along a length of the well bore a monitoring system. The monitoring system includes a swept-wavelength interferometer (SWI) configured to transmit light into the fiber-optic wire by sweeping the light across a range of wavelengths, and the monitoring system is configured to detect a characteristic in the well bore based on detecting a Rayleigh backscatter of the light transmitted into the fiber-optic wire.

Abstract: A system and method to obtain an acoustic signal from a borehole penetrating the earth are described. The system includes a modulated single frequency incoherent light source to output a modulated light signal. The system also includes two or more optical fibers to split the modulated light signal for transmission to an optical sensor in the borehole, at least one of the two or more optical fibers including a delay, two or more photodetectors to receive respective resultant signals resulting from the two or more optical fibers transmitting the modulated light signal to the optical sensor, and a processor to obtain the acoustic signal based on the resultant signals.

Abstract: A method, apparatus and optical network for obtaining a signal from a sensor in a fiber optic cable at a downhole location is disclosed. A reference signal is propagated through the fiber optic cable. A beam of light is received from the fiber optic cable, wherein the beam of light includes the propagated reference signal and the signal from the sensor generated from an interaction of the sensor and the reference signal. The propagated reference signal is obtained from the received beam of light. The signal from the sensors is obtained by sampling the received beam of light using the obtained propagated reference signal.