A system includes at least one optical fiber having at least one FBG and a detection system. The optical fiber is configured to be coupled to a structure in at least one location. The location at which the optical fiber is to be coupled to the structure is different from a location at which the FBG is disposed. The detection system includes a light source configured to inject light into the optical fiber, a photodetector configured to detect a shift in a wavelength spectrum of light reflected by the FBG as a result of a time-varying strain induced at the at least one FBG, and a processor configured to detect a shear-horizontal guided stress wave propagating in said structure based on the shift in the wavelength spectrum detected by the photodetector induced by a longitudinal-type guided stress wave that is propagated along the optical fiber.

A waveguide for guiding an electro-magnetic wave comprises: a first waveguide part; and a second waveguide part; wherein the first waveguide part has a first width in a first direction (Y) perpendicular to the direction of propagation of the electro-magnetic wave and the second waveguide part has a second width in the first direction (Y), wherein the second width is larger than the first width; and wherein the first and the second waveguide parts are spaced apart by a gap in a second direction (Z) perpendicular to the first and second planes in which the waveguide parts are formed, wherein the gap has a size which is sufficiently small such that the first and second waveguide parts unitely form a single waveguide for guiding the electro-magnetic wave.

A photonic integrated circuit component, a sensor and an actuator comprising the waveguide are disclosed.

A fiber optic cable includes a plurality of optical fibers and an optical sensor. The optical sensor includes a first optical coupler and a first mirror. The first optical coupler is coupled to a first of the optical fibers and to a second of the optical fibers at a first sensor takeout location. The first mirror is coupled to the first of the optical fibers at a second sensor takeout location. The first sensor takeout location is longitudinally offset from the second sensor takeout location.

This invention discloses optical strain, stretch, and/or bend sensors which can provide precise and consistent measurement of human motion, posture, and gestures without the locational limitations of camera-based motion capture, the point-estimate limitations of inertial-based motion capture, or the variability of electrically-conductive strain, stretch, and/or bend sensors.

An apparatus includes an enclosure having one or more apertures for receiving therethrough optical fiber, and one or more actuators sealed within the enclosure for generating one or more interference signals for interfering with optical fiber within the enclosure such that an optical path length of the optical fiber is altered. A method for verifying an event detection system includes interrogating optical fiber positioned alongside a conduit by sending one or more light pulses along the optical fiber and receiving reflections of the one or more light pulses. The method further includes using an event verification device housed within an enclosure through which passes the optical fiber to generate one or more interference signals for interfering with the optical fiber such that an optical path length of the optical fiber is altered.

A system and method of determining the center of a peak of data points of an optical sensor are disclosed. The method can comprise the steps of performing an initial setup measurement of the sample points and extracting a peak; fitting the peak with a function that uses at least one of the peak's width, amplitude and center offset as fitting parameters; producing a set of linear equations which when solved calculate the optimum fit of a function to the peak assuming the previously calculated peak's width; and performing subsequent measurements of the data points to find peaks and solving the set of linear equations to determine the center of the peaks.

This invention describes the structure and function of an integrated multi-sensing system. Integrated systems described herein may be configured to form a microphone, pressure sensor, gas sensor or accelerometer. The system uses Fabry-Perot Interferometer in conjunction with beam collimator, beam splitter, optical waveguide and a photodetector integrated. It also describes a configurable method for tuning the integrated system to specific resonance frequency using electrostatic actuators.

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.

The present invention discloses a Fiber Bragg Grating demodulation device with a suppressed fluctuation at a variable ambient temperature and a demodulation method. The device comprises a broadband light source (1), an optical attenuator (2), a tunable F-P filter (3), a first optical fiber isolator (41), an erbium-doped optical fiber amplifier (5), an optical fiber first-stage beam splitter (6), a first optical fiber second-stage beam splitter (71), optical fiber circulators (8), FBG sensor arrays (9), a first photoelectric detector array (161), an optical fiber gas cell (10), a second optical fiber second-stage beam splitter (72), an optical fiber F-P etalon (11), a notch filter (12), an optical fiber assisted interferometer (13), a data acquisition card (17) and a processor (18).

Methods are proposed for compensation of distortion in fiber Fabry-Perot interferometric (FFPI) sensors induced by dynamic wavelength dependent attenuation in subsurface wells. The methods involve measurement techniques that correct the reflective spectrum from one or more FFPI sensors utilizing a background low frequency spectrum for normalization.