A surface shape determination system includes a surface shape sensor in the form of a flexible and stretchable elastomeric substrate with strain/displacement sensing elements embedded in it. The sensor may be a single-core optical fiber with a series of fiber Bragg Gratings (FBGs) located at predetermined positions along its length. A light source provides an incident light spectrum at one end of the fiber. Each grating of the fiber has index modulation which causes particular wavelengths of the light spectrum that do not satisfy the Bragg condition to be reflected back in the fiber. The refractive index of each grating changes with strain on the substrate due to deflection of it. An interrogator captures the reflected wavelengths and retrieves signal information therefrom. A processor receives the output of the interrogator and performs non-linear regression analysis on the information using a neural network to reconstruct the surface morphology in real-time.

A temperature monitoring apparatus configured to monitor a temperature of a portion of a vehicle's electrical energy distribution network is disclosed. The apparatus includes a first optical fibre including one or more temperature sensing sections, each temperature sensing section being for thermal contact with a portion of a vehicle's electrical energy distribution network. Each temperature sensing section is arranged to produce, in response to an optical input signal, an optical output signal indicative of the temperature of the temperature sensing section. The apparatus is arranged to determine a temperature of the portion of the vehicle's electrical energy distribution network based on one or more of the output optical signals in use.

An apparatus has a cassette configured to hold optical fiber comprising one or more optical sensors. The cassette has a spool configured to one or more of extract and retract the optical fiber from the cassette. A pre-strain mechanism is configured to apply a predetermined pre-strain to the one or more optical sensors. An optical fiber installation tool is configured to mount the optical fiber comprising the one or more pre-strained optical sensors to a surface.

The present disclosure relates to an arrangement (100) for obtaining a quantity related to a temperature along a part of an optical fibre (110). The arrangement comprises a light emitter (120) arranged to emit light into the optical fibre (110). The optical fibre is at at least one location along said part of the optical fibre provided with a Fibre Bragg Gratings, FBGs (111, 112, 113), wherein the FBGs are arranged to reflect light within a predetermined wavelength range. The arrangement further comprises a detector (160) arranged to receive and detect the reflected light, a first optical shutter (130) arranged in the optical path after the light emitter. The first optical shutter is arranged to be opened and closed in order to let the emitted light through and into the optical fibre (110), a second optical shutter (150) arranged to be opened and closed in order to let the reflected light through, and an optical circulator (140) having a first, a second and a third port. The optical circulator is operatively connected to the first optical shutter (130) at the first port, to the part of the optical fibre provided with the FBGs (111, 112) at the second port, and to the second optical shutter (150) at the third port. A control unit (180) is arranged to control the first optical shutter (130) and the second optical shutter (150). The control unit (180) is arranged to coordinate the timing of the opening of the first optical shutter (130) and the second optical shutter (150), respectively.

Optical fiber connections and their applications in downhole assemblies are described herein. The downhole assembly includes a well completion element with an end that couples with a corresponding well completion element. An optical fiber extends along at least a portion of the well completion element and transmits an optical signal using a first mode. The well completion element includes an optical fiber connector that is coupled to the optical fiber. The connector also includes a mode converter that receives the optical signal from the optical fiber and converts the optical signal from the first mode to a second larger mode. This second larger mode may be more robustly communicated to a corresponding optical fiber connector affixed to the corresponding well completion element.

Methods for determining sensor channel location in distributed sensing of fiber-optic cables are disclosed. In one method, three or more Fiber Bragg-Gratings (FBGs) connected in series by a standard telecommunication fiber and interrogated using an input distributed fiber-optic sensing (DFOS) laser, where the input DFOS laser has a single wavelength. The input DFOS laser operates on a single wavelength that is different than the respective wavelengths of each of the three or more FBGs. The three or more FBGs are interrogated using an input broadband FBG laser. Each FBG reflects a wavelength of laser light that is proportional to the grating size, using an optical time domain reflectometer (OTDR) at the FBG wavelength, the distance to the particular FBG in the optical domain is computed and compared to the physical measurement of the FBG location. The sensor channel locations of the DFOS system are calibrated and constrained using this method.

The purpose of the present invention is to provide a bonded structure, a method for manufacturing the same, and a bonding state detection method which are capable of determining whether or not members are bonded together appropriately. A bonded structure 10 includes a laminated sheet 12A, a laminated sheet 12B, an adhesive 14 that bonds the laminated sheet 12A and the laminated sheet 12B together, and a distributed optical fiber 16 sandwiched between the laminated sheet 12A and the laminated sheet 12B. The cross-sectional shape of the distributed optical fiber 16 is deformed in accordance with the bonding state.

Embodiments of present invention provide a digital dispersion compensation module. The digital dispersion compensation module includes a multi-port optical circulator and a plurality of dispersion compensation units connected to the multi-port optical circulator, wherein at least one of the plurality of dispersion compensation units includes a first and a second reflectively terminated element and an optical switch being capable of selectively connecting to one of the first and second reflectively terminated elements, and wherein the at least one of the plurality of dispersion compensation units is adapted to provide a substantially zero dispersion to an optical signal, coming from the multi-port optical circulator, when the optical switch connects to the first reflectively terminated element and is adapted to provide a non-zero dispersion to the optical signal when the optical switch connects to the second reflectively terminated element.

Optical fiber connections and their applications in downhole assemblies are described herein. The downhole assembly includes a well completion element with an end that couples with a corresponding well completion element. An optical fiber extends along at least a portion of the well completion element and transmits an optical signal using a first mode. The well completion element includes an optical fiber connector that is coupled to the optical fiber. The connector also includes a mode converter that receives the optical signal from the optical fiber and converts the optical signal from the first mode to a second larger mode. This second larger mode may be more robustly communicated to a corresponding optical fiber connector affixed to the corresponding well completion element.

A polymer composite wireline cable comprising: a polymeric matrix material; at least one reinforced fiber embedded in the polymeric matrix material; and at least one optical fiber disposed in the polymeric matrix material, the at least one optical fiber having at least one pair of Bragg grating sensors, wherein one of the pair of Bragg grating sensors is configured to experience loading strain and the other of the pair of Bragg grating sensors is configured not to experience loading strain.