An optical storage device for storing data includes at least one optical waveguide for receiving an optical interrogation signal and providing a response to the optical interrogation signal and a plurality of optical elements arranged relative to the at least one optical waveguide. The plurality of optical elements are responsive to the optical interrogation signal provided through the at least one waveguide to return a prescribed data value through the at least one optical waveguide. The plurality of optical elements represent encoded data concerning a function of an optical sensor.

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 method of determining an optical transform imparted by a multimode optical fibre (300) is disclosed. The wherein the multimode fibre (300) comprises a proximal end, a distal end, and at least one modified region (260) between the proximal end and distal end. The modified region (260) is configured to transmit light toward the proximal end in response to light propagating through the multimode optical fibre (300) from the proximal end to the distal end. The method comprises coupling (101) forward propagating light into the proximal end of the multimode optical fibre; detecting (102), at the proximal end, backward propagating light transmitted from the at least one modified region in response to the forward propagating light; and determining (103) an optical transform from the detected backward propagating light.

A sensor includes at least one optical waveguide having a mode-field diameter greater than 11 m and an optical reflector optically coupled to the at least one optical waveguide. The optical reflector includes a first substrate portion configured to reflect a first portion of a light beam back to the at least one optical waveguide and a diaphragm configured to reflect a second portion of the light beam back to the at least one optical waveguide. The diaphragm is responsive to a perturbation by moving relative to the first substrate portion. The light beam is centered on a region between the first substrate portion and the diaphragm.

This application relates to methods and apparatus for distributed fibre optic sensor and especially to Rayleigh based distributed fibre optic sensing that provides enhanced or additional information, such as information regarding large amplitude strains. A sensor has an interrogator (102) for interrogating a sensing optical fibre (101) to perform distributed acoustic sensing and provide a measurement signals from each of a plurality of channels corresponding to sensing portions of the sensing optical fibre. A processor (106, 107) analyses the measurement signals to detect a first characteristic signature (203), the first characteristic signature being a variation in the measurement signal from a plurality of channels that applies for a first channel and substantially all downstream channels and which occurs simultaneously on all such channels.

A method and system of compensating for body deformation during image acquisition or external beam treatment includes acquiring image data of a body and peak wavelength data from a plurality of fiber Bragg gratings (FBGs) disposed on the body aligned along a predetermined coordinate system on the body, such as a cartesian coordinate system. The method further comprises detecting effective shifts of the Bragg wavelengths of the FBGs caused by body deformation during image acquisition, and controlling the movement of the body through a cavity in a scanning device and controlling the acquisition of the image data or external beam treatment during body deformation based on the effective shifts of the Bragg wavelengths of the FBGs.

An infrared sensing module includes a reflecting portion, a driving portion, an infrared light emitter and an infrared light receiver. The driving portion is connected to the reflecting portion, and the driving portion drives the reflecting portion to rotate, and an infrared reflecting layer of the reflecting portion faces the infrared light emitter and the infrared light receiver when the reflecting portion rotates to a preset position.

A displacement sensor has a graded index multi-mode fiber with a length that is an odd multiple of a quarter pitch length of the graded index multi-mode fiber and a single-mode optical fiber fusion spliced to the first end of said graded index multi-mode fiber. A reflective mirror coating is applied to a planar facet on the second end of said graded index multi-mode fiber. A plurality of mechanical attachments are spaced along the graded index multi-mode fiber and single-mode optical fiber that mechanically deform said graded index multi-mode fiber, when any one of said plurality of mechanical attachments is displaced relative to any other one of said plurality of mechanical attachments.

A method and system of compensating for body deformation during image acquisition or external beam treatment includes acquiring image data of a body and peak wavelength data from a plurality of fiber Bragg gratings (FBGs) disposed on the body aligned along a predetermined coordinate system on the body, such as a cartesian coordinate system. The method further comprises detecting effective shifts of the Bragg wavelengths of the FBGs caused by body deformation during image acquisition, and controlling the movement of the body through a cavity in a scanning device and controlling the acquisition of the image data or external beam treatment during body deformation based on the effective shifts of the Bragg wavelengths of the FBGs.

A spectral interrogation device, including: an optical source for emitting a light signal, a measurement optical fibre comprising a series of successive Bragg gratings for reflecting the light signal in different wavelength bands, a reflective optical fibre comprising a total reflection element, a wavelength detector, and an optical switch for switching between a sequence of three operating modes. In a first mode, the light signal emitted by a given optical source is guided from the optical source to a corresponding measurement optical fibre. In a second mode, the light signal is guided to make a predetermined number of return trips in a line formed by a coupling between the measurement optical fibre and a corresponding reflective optical fibre, generating a predetermined delay between the successive gratings. In a third mode, the light signal is guided to a corresponding detector to successively measure the wavelength bands associated with the gratings.