A monitoring system is disclosed herein that is configured to utilize a distributed sensing system to monitor both a cable and cable accessories included within a cable circuit. In various embodiments, the monitoring system may include a distributed sensing system and one or more cable accessory wrap assemblies. The distributed sensing system may include a distributed sensing fiber following (or integrated into) the cable and connected to a cable accessory wrap assembly for each of the one or more cable accessories in-line with cable. In various embodiments, each cable accessory wrap assembly may comprise a cable wrap embedded with a distributed sensing fiber. The distributing sensing fiber of a cable accessory wrap assembly may be configured to provide measurements to distributed sensing system indicating that an anomaly event occurred at a given cable accessory.

A distributed acoustic sensing (DAS) system based on space-division multiplexing with multi-core fiber (MCF) is proposed. It relates to a technical field of distributed optical fiber sensing. The present invention maintains the advantage of single-ended measurement in the standard DAS system, and realizes the intensity accumulation of the Rayleigh backscattering light within each core of the MCF, which can greatly improve the strain resolution of DAS systems. Moreover, the introduction of optical switch can make different code sequences transmit in the different core of the MCF simultaneously, which can make the single-pulse response with coding gain demodulated without sacrificing the frequency responding bandwidth. Furthermore, the utilization of space-division multiplexing can make multiple pulses with precious time delay transmit in the MCF simultaneously, which can greatly improve the frequency responding bandwidth of DAS system.

A system is provided with a measurement system having a light source, a light sensor, and a controller coupled to the light source and the light sensor. The controller is configured to determine a clearance between a rotor and a casing at least partially based on an interruption of light transmitted from the light source to the light sensor.

A system is provided with a measurement system having a light source, a light sensor, and a controller coupled to the light source and the light sensor. The controller is configured to determine a clearance between a rotor and a casing at least partially based on an interruption of light transmitted from the light source to the light sensor.

An interrogation system may be coupled to a fiber-optic cable positioned in a wellbore to interrogate a plurality of optical sensors coupled to the fiber-optic cable. The interrogation system may include an optical frequency comb source having a plurality of narrowband optical carriers transmitting light to the plurality of optical sensors. Each of the plurality of optical sensors may include a pair of partial reflectors to reflect the light transmitted by the optical frequency comb to one or more optical receivers to receive the reflection signals In some aspects, the interrogation system may include a de-interleaver device for separating reflected light signals having adjacent wavelength into separate optical waveguides. In additional aspects, interrogation system may also include a data processing system having a processing device for performing interferometric measurements using the reflected light signals.

An interrogation system may be coupled to a fiber-optic cable positioned in a wellbore to interrogate a plurality of optical sensors coupled to the fiber-optic cable. The interrogation system may include an optical frequency comb source having a plurality of narrowband optical carriers transmitting light to the plurality of optical sensors. Each of the plurality of optical sensors may include a pair of partial reflectors to reflect the light transmitted by the optical frequency comb to one or more optical receivers to receive the reflection signals In some aspects, the interrogation system may include a de-interleaver device for separating reflected light signals having adjacent wavelength into separate optical waveguides. In additional aspects, interrogation system may also include a data processing system having a processing device for performing interferometric measurements using the reflected light signals.

A system and methods for providing optical, downhole data communication without requiring a light source in the downhole tool is disclosed. A carrier signal generated at the surface is sent to the downhole tool using an optical fiber. An optical modulator of the downhole tool uses data signals from a sensor to modulate the carrier signal based on the data signals. The modulated signal is transmitted to one or more optical receivers. The optical modulator can be coupled to the one or more optical receivers through the same optical fiber as the carrier signal generator, or one or more additional optical fibers.

A system and methods for providing optical, downhole data communication without requiring a light source in the downhole tool is disclosed. A carrier signal generated at the surface is sent to the downhole tool using an optical fiber. An optical modulator of the downhole tool uses data signals from a sensor to modulate the carrier signal based on the data signals. The modulated signal is transmitted to one or more optical receivers. The optical modulator can be coupled to the one or more optical receivers through the same optical fiber as the carrier signal generator, or one or more additional optical fibers.

A drop-detection device detects a drop that escapes from a metering valve. The drop-detection device includes a light guide with first and second light-guiding elements that are arranged opposite each other at an intermediate space. A drop trajectory runs through the intermediate space such that a light beam sent out by the first light-guiding element crosses the drop trajectory and is subsequently coupled into the second light-guiding element. In addition, the drop-detection device includes a light-signal generation device that couples a pulsed light beam with a carrier frequency into the first light-guiding element. Furthermore, the drop-detection device also has a light evaluation device for evaluating the light beam coupled into the second light-guiding element to determine if a drop has been dispensed by the metering valve. A method of detecting a drop is also described.

A drop-detection device detects a drop that escapes from a metering valve. The drop-detection device includes a light guide with first and second light-guiding elements that are arranged opposite each other at an intermediate space. A drop trajectory runs through the intermediate space such that a light beam sent out by the first light-guiding element crosses the drop trajectory and is subsequently coupled into the second light-guiding element. In addition, the drop-detection device includes a light-signal generation device that couples a pulsed light beam with a carrier frequency into the first light-guiding element. Furthermore, the drop-detection device also has a light evaluation device for evaluating the light beam coupled into the second light-guiding element to determine if a drop has been dispensed by the metering valve. A method of detecting a drop is also described.