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 high backscattering optical fiber comprising a perturbed segment in which the perturbed segment reflects a relative power such that the optical fiber has an effective index of n.sub.eff, a numerical aperture of NA, a scatter of R.sub.p.fwdarw.r.sup.(fiber) that varies axially along the optical fiber, a total transmission loss of α.sub.fiber, an in-band range greater than one nanometer (1 nm), and a figure of merit (FOM) in the in-band range. The FOM being defined as:

[00001]$FOM=\frac{R_{p.fwdarw.r}^{\left(\mathrm{fiber}\right)}}{{{\alpha }_{\mathrm{fiber}}\left(\frac{\mathrm{NA}}{2n_{\mathrm{eff}}}\right)}^2}.$

An optical-fiber-embedding sheet which is a strip-shaped sheet material containing an optical fiber to be used as a sensor and is configured of a base material and an adhesive layer formed thereover which is to be bonded to a placement object where the optical fiber is to be placed, the optical fiber having been embedded in the adhesive layer. The optical fiber is placed by applying a primer, which is for curing the adhesive layer by a chemical reaction with the adhesive layer, to a placement object for the optical fiber and thereafter applying the optical-fiber-embedding sheet to the portion of the placement object to which the primer has been applied.

A multibend sensor has a plurality of electrodes located along the sliding or reference strip that are not uniformly paced. More electrodes can be placed in those regions where more precise measurements of movement are desired. To save costs fewer electrodes need to be placed in regions where there is no need to measure the bending.

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 elongate multi-core optical fiber instrument for insertion within a patient body includes a set of first optical fiber cores extending along a first sensing region of the multi-core optical fiber instrument, where each first optical fiber core includes a set of first sensors disposed along the first region and a set of second optical fiber cores extending along a second sensing region of the multi-core optical fiber instrument, where each second optical fiber core includes a set of second sensors disposed along the second sensing region. The first sensing region is located distal the second sensing region, and the first optical fiber cores extend along the second sensing region. Also disclosed is a console for providing an incident light signal to the multi-core optical fiber instrument, receiving reflected light signals from the sensors, and determining a parameter experienced by instrument in accordance with the reflected light signals.

There is described a method for interrogating optical fiber comprising fiber Bragg gratings (“FBGs”), using an optical fiber interrogator. The method comprises (a) generating an initial light pulse from phase coherent light emitted from a light source, wherein the initial light pulse is generated by modulating the intensity of the light; (b) splitting the initial light pulse into a pair of light pulses; (c) causing one of the light pulses to be delayed relative to the other of the light pulses; (d) transmitting the light pulses along the optical fiber; (e) receiving reflections of the light pulses off the FBGs; and (f) determining whether an optical path length between the FBGs has changed from an interference pattern resulting from the reflections of the light pulses.

Shape-sensing systems and methods for medical devices. The shape-sensing system can include a medical device, an optical interrogator, a console, and a display screen. The medical device can include an integrated optical-fiber stylet having fiber Bragg grating (“FBG”) sensors along at least a distal-end portion thereof. The optical interrogator can be configured to send input optical signals into the optical-fiber stylet and receive FBG sensor-reflected optical signals therefrom. The console can be configured to convert the reflected optical signals with the aid of filtering algorithms of some optical signal-converter algorithms into plottable data for displaying plots thereof on the display screen. The plots can include a plot of curvature vs. time for each FBG sensor of a selection of the FBG sensors for identifying a distinctive change in strain of the optical-fiber stylet as a tip of the medical device is advanced into a superior vena cava of a patient.

An apparatus comprises a flexible filament structure, and a fiber optic sensor with a buffer material that locally bonds the fiber optic sensor to the flexible filament structure to create a bond between the fiber optic sensor and the flexible filament structure to transfer strain from the flexible filament structure to the fiber optic sensor to allow the fiber optic sensor to detect strain on the flexible filament structure while maintaining flexibility in the flexible filament structure. A fiber optic interrogator may be optically coupled to the fiber optic sensor and configured to measure strain. A method comprises embedding a fiber optic sensor with a buffer material in or on a flexible filament structure. Thereafter, the buffer material is activated via heating or curing to locally adhere the fiber optic sensor to the flexible filament structure to create a local bond. The local bond transfers strain from the flexible filament structure to the fiber optic sensor.

An assembly having a bearing with an axis of rotation, and a fibre-based sensor for sensing strain or temperature of the bearing is disclosed. The sensor extends in a direction parallel to the axis of rotation. An aircraft system is disclosed including a wheel supported on an axle by a first bearing and a second bearing. The system further includes a first fibre optic sensor for sensing a strain or temperature of the first bearing, a second fibre optic sensor for sensing a strain or temperature of the second bearing, and an interrogator to analyse optical signals from the sensors to determine differences in the strains or temperatures of the first bearing and the second bearing.