Disclosed are an apparatus for measuring a displacement using a fiber Bragg grating sensor, which is applied to a strain sensor using the fiber Bragg grating sensor, and a method of controlling sensitivity and durability of the same. The apparatus includes: a case forming an external appearance; third and fourth optical fibers having mutually different numbers of strands and installed in the case while being spaced apart from each other by a predetermined interval; and a connection unit installed between the third and fourth optical fibers and fixed at a predetermined position by tension applied to the third and fourth optical fibers, wherein the fiber Bragg grating sensor is installed to one selected from the pair of optical fibers having mutually different numbers of strands, so that measurement sensitivity and durability are controllable.

A sensing system that includes an optical fiber disposed helically around an outer surface of a structure along a longitudinal axis of the structure is provided. The optical fiber is disposed such that at least one complete helical turn of the optical fiber covers the length of the structure. Further, the sensing system also includes a fiber Bragg grating (FBG) set comprising a plurality of FBGs in the optical fiber. Each FBG in the set is configured to generate reflected light that is indicative of strain values at a location of each respective FBG on the optical fiber. Furthermore, the system also includes a processing system coupled to the optical fiber. The processing system is configured to determine location coordinates of each FBG and values of one or more of bending moment, tensile force, and torsional moment acting at each FBG location on the optical fiber.

An apparatus, system and method determining a position of an instrument (100) are provided. A sheath (104) is configured to fit within an instrument channel of a medical scope. An optical fiber (112) is disposed within the sheath and a plurality of sensors (106) is integrated in optical fiber. The sensors are configured to measure deflections and bending in the optical fiber. A fixing mechanism (140) is sized to fit within the instrument channel in a first state and fixes the sheath within the instrument channel in a second state such that the fixing mechanism anchors the sheath and the optical fiber so that the deflections and bending in the optical fiber are employed with a pre-procedural volumetric image to determine a position of the instrument.

The present invention relates to an optical fiber sensor for shape sensing, comprising an optical fiber having embedded therein a number of at least four fiber cores (1 to 6) arranged at a distance from a longitudinal center axis (0) of the optical fiber, the number of fiber cores (1 to 6) including a first subset of at least two fiber cores (1, 3, 5) and a second subset of at least two fiber cores (2, 4, 6), the fiber cores (2, 4, 6) of the second subset being arranged to provide a redundancy in a shape sensing measurement of the fiber sensor (12). The fiber cores (1, 3, 5) of the first subset are distributed in azimuthal direction around the center axis (0) with respect to one another, and each fiber core (2) of the second subset is arranged in non-equidistantly fashion in azimuthal direction around the center axis (0) with respect to two neighboring fiber cores (1, 3) of the first subset.

Embodiments described herein relate to methods and apparatuses for determining information associated with an optical component system in a network. A method for determining information associated with an optical component system in a network, wherein the optical component system includes a first optical path for transmission of a first optical signal, wherein the first optical path operates in an optical bandwidth that is different from a traffic optical bandwidth of a traffic optical path, includes: detecting at least one mechanically introduced optical loss in the transmitted first optical signal; and based on the detected at least one mechanically introduced optical loss, determining information associated with the optical component system.

A method for forming a pressure sensor is provided wherein an optical fibre is provided, the optical fibre comprising a core, a cladding surrounding the core, and a birefringence structure for inducing birefringence in the core. The birefringence structure comprises first and second holes enclosed within the cladding and extending parallel to the core. A portion of the optical fibre comprising the core and the birefringence structure is encased within a chamber, wherein the chamber is defined by a housing comprising a pressure transfer element for equalising pressure between the inside and the outside of the housing. An optical sensor is provided along the core of the optical fibre. Providing the optical sensor comprises optically inducing stress in the core so that the optical sensor exhibits intrinsic birefringence. The chamber is filled with a substantially non-compressible fluid. Consequently, the birefringence structure is shaped so as to convert an external pressure provided by the non-compressible fluid within the chamber to an anisotropic stress in the optical sensor.

A fiber Bragg grating sensor arrangement includes a resonant cavity light emitting diode for outputting light; a fiber having a first end disposed to receive light output from the resonant cavity light emitting diode, the fiber including fiber Bragg grating etched at one or more locations along a length thereof. A strain mount or beam supports the fiber and to which the fiber is attached or bonded. A light detection circuit disposed at a second end of the fiber receives light traveling through the fiber, the light detection circuit sensing intensity of the received light that corresponds to strain or force applied to the fiber that is bonded to the strain mount. Another fiber Bragg grating sensor arrangement includes a second reference fiber that does not receive a force or strain. The reference fiber provides an output used to prevent temperature/humidity from affecting the output of the FBG sensor arrangement.

A curvature sensor includes a light source, a flexible light guide including cores, and FBG sensors that are provided in the cores and constitute FBG sensor groups at predetermined positions at predetermined positions along longitudinal axes of the cores. The curvature sensor includes a detector that detects an optical spectrum of light from the FBG sensors, and a processor that obtains a bend of the light guide. FBG sensors provided in a core include a first FBG sensor and a second FBG sensor next to it. The first and second FBG sensors include gratings having first and second pitches. The first pitch is shorter than the second pitch and is closer to the second pitch than other pitches of gratings of all FBG sensors that are provided in the core and include gratings having pitches shorter than the second pitch.

A curvature sensor includes a light source, a flexible light guide including cores, FBG sensors that are provided in the cores and constitute FBG sensor groups at predetermined positions along longitudinal axes of the cores. The curvature sensor includes a detector that detects an optical spectrum of light from the FBG sensors, and a processor that determines a bend position and a bend amount of the light guide. The FBG sensor groups include a first FBG sensor group and a second FBG sensor group next to it. FBG sensors in the first and second FBG sensor groups include gratings having first and second pitches. The first pitch is shorter than the second pitch and is closer to the second pitch than other pitches of gratings of FBG sensors that include gratings having pitches shorter than the second pitch.

An apparatus for sensing acoustic waves below a surface of the earth includes an optical fiber disposed below the surface of the earth and having a series of sensing units along the optical fiber with each sensing unit having three or more reflectors and an optical interrogator in optical communication with the optical fiber. The reflectors in each sensing unit are positioned to provide a linearized response that approximates a sawtooth wave better than a sinusoidal wave to sense the acoustic waves in a desired dynamic range. The optical interrogator is configured to transmit an input light signal into the optical fiber and receive a reflected light signal from the optical fiber due to the input light signal in order to measure a strain on each sensing unit due to interaction with the acoustic waves and to determine a location of the sensing unit corresponding to the sensed strain.