The application provides a interface light path structure with all polarization-maintaining function. A first polarization-maintaining-transferring device includes a first port, a second port, and a third port, wherein the first port receives a first polarized light output by the polarization beam-splitting device, the second port is connected to the first Faraday rotation mirror, and the third port is connected to a first port of the first polarization-maintaining coupler. A second polarization-maintaining-transferring device includes a first port, a second port, and a third port, wherein the first port receives a second polarized light output by the polarization beam-splitting device, the second port is connected to the second Faraday rotation mirror, and the third port is connected to a second port of the first polarization-maintaining coupler.

A hybrid sensing apparatus for collecting data inside a well, the apparatus including an optical cable that acquires a first set of data; and an array of discrete probes connected to each other with an electrical cable. The discrete probes are configured to acquire a second set of data. The apparatus further includes an attachment system attached to the discrete probes and configured to hold the optical cable. The attachment system is configured to expose the optical cable to directly contact the well.

A production monitoring system includes a distributed acoustic sensing subsystem that includes a first optical fiber for a distributed acoustic sensing signal and a distributed temperature sensing subsystem that includes a second optical fiber for a distributed temperature sensing signal. The production monitoring system, also includes a cable positioned in a wellbore penetrating through one or more subterranean formations. The distributed acoustic sensing subsystem is communicatively coupled to the cable through the distributed temperature sensing subsystem. The cable includes one or more optical fibers used to obtain optical fiber measurements pertaining to the distributed acoustic sensing signal and the distributed temperature sensing signal. The optical fibers include a sensing fiber that is common between the distributed acoustic sensing subsystem and the distributed temperature sensing subsystem. The distributed acoustic sensing subsystem, receives at least a portion of the optical fiber measurements from the sensing fiber through the distributed temperature sensing subsystem.

An optical system performs a method for measuring an acoustic signal in a wellbore. The optical system includes a light source, an optical fiber and a detector. The light source generates a light pulse. The optical fiber has a first end for receiving the light pulse from the light source and a plurality of enhancement scatterers spaced along a length of the optical fiber for reflecting the light pulse. A longitudinal density of the enhancement scatterers increases with a distance from the first end to increase a signal enhancement generated by the enhancement scatterers distal from the first end. The detector is at the first end of the optical fiber and measures a reflection of the light pulse at the enhancement scatterers to determine the acoustic signal.

Optical whispering gallery mode (WGM) resonator-based acoustic sensors, imaging systems that make use of the acoustic sensors, and methods of detecting ultrasound waves using the acoustic sensors are disclosed.

An object of the present disclosure is to detect a microbend in an optical fiber before the light-receiving intensity of a transmission device decreases. The present disclosure relates to a device configured to measure guided acoustic wave Brillouin scattering in a measurement target optical fiber, and detect a microbend in the measurement target optical fiber based on a characteristic around a peak of the guided acoustic wave Brillouin scattering.

Systems and methods for alignment and testing of a photonic device include a light source, an interferometer, a detector, and a processing circuit. The processing circuit may generate control signal(s) for the light source to project a beam through the interferometer to a device under testing (DUT). The interferometer may receive an interference beam from an optical fiber of the DUT. The processing circuit may align optical fiber(s) for the DUT, determine one or more characteristics for the DUT, and so forth based on the interference beam and a reference beam generated by the interferometer.

An optical fiber distributed sensing system may include an optical fiber for distributed sensing. The optical fiber may include a core including glass and diamond particles with nitrogen-vacancy (NV) centers distributed within the glass. The optical fiber may also include at least one glass layer surrounding the core. An optical source may be coupled to the optical fiber and operable from an end thereof. An optical detector may be coupled to the optical fiber to detect fluorescence therefrom.

A detection system in an aircraft includes an optical fiber arranged along a structure of the aircraft and affixed to the structure with clamps that are spaced apart along the structure. The optical fiber includes two or more sets of fiber Bragg gratings (FBGs). The system also includes a light source to generate light with two or more wavelengths for injection into the optical fiber, and processing circuitry to identify an overheat condition and monitor vibration experienced by the optical fiber based on reflected signals generated by the two or more sets of FBGs. Integrity of the clamps is indicated by monitoring the vibration.

An optical fiber sensing system according to the present disclosure includes an optical fiber (10) provided on a water discharge gate (30) of a reservoir or in a vicinity of the water discharge gate (30), a reception unit (21) configured to receive an optical signal including a vibration pattern from the optical fiber (10), and a detection unit (22) configured to detect whether an opening amount of the water discharge gate (30) is appropriate, based on a vibration pattern included in the optical signal.