Abstract: An embodiment of a method of manufacturing a fiber optic cable includes selecting a cable support structure configured to support an optical fiber sensor, adhering the optical fiber sensor to the cable support structure by applying a temporary adhesive, and installing a protective layer around the cable support structure and the temporarily adhered optical fiber sensor. The method further includes removing a bond between the optical fiber sensor and the temporary adhesive, wherein removing the bond includes injecting a debonding material into a space formed between the cable support structure and the protective layer, and injecting a permanent adhesive into the space, the permanent adhesive configured to immobilize the optical fiber sensor relative to the protective layer and allow strain to be transferred from the protective layer to the optical fiber sensor.

Abstract: An embodiment of a method of manufacturing a fiber optic cable includes selecting a cable support structure configured to support an optical fiber sensor, adhering the optical fiber sensor to the cable support structure by applying a temporary adhesive, and installing a protective layer around the cable support structure and the temporarily adhered optical fiber sensor. The method further includes removing a bond between the optical fiber sensor and the temporary adhesive, wherein removing the bond includes injecting a debonding material into a space formed between the cable support structure and the protective layer, and injecting a permanent adhesive into the space, the permanent adhesive configured to immobilize the optical fiber sensor relative to the protective layer and allow strain to be transferred from the protective layer to the optical fiber sensor.

Abstract: A method for producing a protected optical fiber with distributed sensors includes heating an optical fiber preform and drawing the heated optical fiber preform to form a drawn optical fiber. The method also includes coating the drawn optical fiber with a carbon coating after the optical fiber is drawn to provide a carbon coated optical fiber and then writing a series of fiber Bragg gratings (FBGs) into the carbon coated optical fiber to provide a carbon coated optical fiber with FBGs. The method further includes coating the carbon coated optical fiber with FBGs with one or more layers of a polymer to provide the protected optical fiber with distributed sensors, wherein the heating, drawing, carbon coating the drawn optical fiber, writing, coating the carbon coated optical fiber are performed in that sequence while the protected optical fiber is being produced.

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: An embodiment of a method of manufacturing a fiber optic cable includes selecting a cable support structure configured to support an optical fiber sensor, adhering the optical fiber sensor to the cable support structure by applying a temporary adhesive, and installing a protective layer around the cable support structure and the temporarily adhered optical fiber sensor. The method further includes removing a bond between the optical fiber sensor and the temporary adhesive, wherein removing the bond includes injecting a debonding material into a space formed between the cable support structure and the protective layer, and injecting a permanent adhesive into the space, the permanent adhesive configured to immobilize the optical fiber sensor relative to the protective layer and allow strain to be transferred from the protective layer to the optical fiber sensor.

Abstract: A apparatus for monitoring a downhole component is disclosed. The apparatus includes: an optical fiber sensor including a plurality of sensing locations distributed along a length of the optical fiber sensor; an interrogation assembly configured to transmit an electromagnetic interrogation signal into the optical fiber sensor and receive reflected signals from each of the plurality of sensing locations; and a processing unit configured to receive the reflected signals, select a measurement location along the optical fiber sensor, select a first reflected signal associated with a first sensing location in the optical fiber sensor, the first sensing location corresponding with the measurement location, select a second reflected signal associated with a second sensing location in the optical fiber sensor, estimate a phase difference between the first signal and the second signal, and estimate a parameter of the downhole component at the measurement location based on the phase difference.

Abstract: A strain sensing cable including one or more strain sensing elements and a strain transfer medium extruded directly onto the one or more strain sensing elements disposed within the strain transfer medium. The strain transfer medium is operatively arranged to transfer strain experienced by the cable to the one or more strain sensing elements. A method of making a strain sensing cable is also included.

Abstract: A strain sensing cable including one or more strain sensing elements and a strain transfer medium extruded directly onto the one or more strain sensing elements disposed within the strain transfer medium. The strain transfer medium is operatively arranged to transfer strain experienced by the cable to the one or more strain sensing elements. A method of making a strain sensing cable is also included.

Abstract: A method for estimating a distance includes: generating an optical signal having a wavelength that is within a wavelength range, the optical signal modulated via a modulation signal having a modulation frequency; transmitting the modulated optical signal from a light source into the optical fiber, the optical fiber in contact with a moveable strain inducing element located at the position along the optical fiber, the optical fiber including a plurality of sensing locations configured to reflect light within the wavelength range when under strain from the strain inducing element and transmit light within the wavelength range when not under strain from the strain inducing element; receiving a reflected signal including light reflected from at least one of the sensing locations; demodulating the reflected signal with a reference signal to generate reflected signal data; and determining the distance to the position along the optical fiber based on the reflected signal data.

Abstract: A method of producing a coated FBG optical fiber involves coating the optical fiber prior to writing the Bragg grating. A system for producing the coated FBG optical fibers includes a high temperature furnace from which to draw the fiber, a coating applicator that may be a carbon coating applicator, a cooling station, and a grating writing station.

Abstract: A method for estimating a distance includes: generating an optical signal having a wavelength that is within a wavelength range, the optical signal modulated via a modulation signal having a modulation frequency; transmitting the modulated optical signal from a light source into the optical fiber, the optical fiber in contact with a moveable strain inducing element located at the position along the optical fiber, the optical fiber including a plurality of sensing locations configured to reflect light within the wavelength range when under strain from the strain inducing element and transmit light within the wavelength range when not under strain from the strain inducing element; receiving a reflected signal including light reflected from at least one of the sensing locations; demodulating the reflected signal with a reference signal to generate reflected signal data; and determining the distance to the position along the optical fiber based on the reflected signal data.

Abstract: A method for estimating a parameter includes: generating an optical signal, the optical signal modulated via a modulation signal having a variable modulation frequency over a period of time; transmitting the modulated optical signal from a light source into an optical fiber, the optical fiber including at least one sensing location configured to reflect light; receiving a reflected signal including light reflected from the at least one sensing location; and demodulating the reflected signal with a reference signal, the reference signal including a time delay relative to the modulation signal based on a distance between the light source and the at least one sensing location.

Abstract: A apparatus for monitoring a downhole component is disclosed. The apparatus includes: an optical fiber sensor including a plurality of sensing locations distributed along a length of the optical fiber sensor; an interrogation assembly configured to transmit an electromagnetic interrogation signal into the optical fiber sensor and receive reflected signals from each of the plurality of sensing locations; and a processing unit configured to receive the reflected signals, select a measurement location along the optical fiber sensor, select a first reflected signal associated with a first sensing location in the optical fiber sensor, the first sensing location corresponding with the measurement location, select a second reflected signal associated with a second sensing location in the optical fiber sensor, estimate a phase difference between the first signal and the second signal, and estimate a parameter of the downhole component at the measurement location based on the phase difference.