A Fabry-Prot sensor assembly includes an optical element defining a Fabry-Prot optical cavity therein. A sensor ferrule is affixed to the optical element. The sensor ferrule is configured to physically connect to an optical fiber, optically aligning and spacing the optical fiber with the optical cavity. The sensor ferrule defines a bore for receiving the optical fiber. The bore extends along a longitudinal axis that extends to the optical element. The optical cavity is a second optical member defined between a first optical member and a third optical member spaced apart from the first optical member along the longitudinal axis. At least one of the first optical member and the third optical member includes a radiused surface bounding the optical cavity and spanning across the optical cavity laterally relative to the longitudinal axis.

An optical waveguide device that enables single-mode coupling between cores to be coupled by controlling optical signal intensity variation due to an MPI. The optical waveguide device includes a first device end surface, a second device end surface, a waveguide, and a cladding layer. The waveguide has a first waveguide end surface and a second waveguide end surface, and light beams of a plurality of modes having different orders are guided. Further, the waveguide has one or more bent portions. The cladding layer has a refractive index lower than a refractive index of the waveguide. The waveguide has a waveguide length L of 510.sup.6 [nm] or more and 10010.sup.6 [nm] or less, and has a structure in which an inter-mode group delay time difference 1 satisfies a condition given by |1|10.sup.12 [s]/L.

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.

A system, apparatus and method directed to detecting malposition of a medical device within a vessel of a patient, such as an Azygos vein. The medical device can include a multi-core optical fiber including a plurality of core fibers, where each of the plurality of core fibers includes a plurality of sensors is configured to reflect a light signal based on received incident light, and change a characteristic of the reflected light signal for use in determining a physical state of the multi-core optical fiber. The system can include a console having non-transitory computer-readable medium storing logic that, when executed, causes operations of providing a broadband incident light signal to the multi-core optical fiber, receiving reflected light signals, processing the reflected light signals, and determining whether the medical device has entered the Azygos vein of the patient based on the reflected light signals.

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.

An annular small-period-long-period fiber grating (SP-LPG) sensor, a preparation method and applications thereof are provided. The annular (SP-LPG) sensor matches the cross-section shape of the optical fibers, the annulus can expand the area of the refractive index modulation region more effectively in the section of the optical fibers, so that the annular grating has a large refractive index modulation region in both the axial and longitudinal directions of the optical fibers, which can simultaneously enhance the intensity of the Bragg resonance peak and the resonance peaks of the cladding modes. Therefore, the Bragg resonance peak and the resonance peaks of the cladding modes can be observed simultaneously in the transmission spectra. It can realize the simultaneous measurement of the refractive index and temperature of the surrounding environment without the need to observe the reflection peak, which simplifies the multi-parameter sensing test steps of the (SP-LPG) sensor.

The present invention discloses an integrated system for optical fiber sensing and communication through sharing co-frequency resources. Specifically, the system consists of two parts: optical path detection and circuit demodulation. The entire system consists of a continuous wave laser, a fiber coupler, a polarization controller, a mach-zehnder modulator, an arbitrary waveform generator, an erbium-doped fiber amplifier, an optical filter, an optical fiber annular, an optical fiber, a photodetector, a data acquisition device, a balance detector and a data acquisition card. A transmission optical signal and a sensing detection light are generated by the same laser, transmission performance and sensing performance of the system are changed by adjusting modulation power of a transmission signal, the transmission signal is obtained by using direct detection at far-end, a sensing signal is obtained by using heterodyne coherent detection at local-end. The present invention provides a simple, compact and high-efficiency integrated system for co-frequency sharing optical fiber sensing and communication, to solve the deficiencies of the existing integrated system in practical applications.

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.

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.

There is disclosed an optical sensor for detecting one or more measurands such as temperature or pressure, comprising a probe light source arranged to generate probe light, and a sensor head arranged to receive the probe light from the probe light source and impose on the probe light an interference signal responsive to the one or more measurands. The sensor then also comprises an interrogator arranged to receive the probe light from the sensor head, measure the imposed interference signal, and determine the one or more measurands from the measured interference signal, and an optical fibre arranged to carry the received probe light at least some of the way from the sensor head to the interrogator, wherein the optical fibre is disposed within a protective conduit. A granular material may then be packed within the conduit so as to restrict or prevent lateral movement of the optical fibre within the conduit. The optical fibre may also or instead be disposed within one or more flexible sleeves within the conduit.