Abstract: The present invention relates to a method of representing shape of an optical fiber sensor (12) having a central core (16) and a plurality of outer cores (14, 18, 20), each core comprising one or more sensing elements, the method comprising: (a) optically interrogating the cores (14, 16, 18, 20) of the fiber sensor (12) from an incident optical wave over a wavelength range centered on a resonance wavelength of the one or more sensing elements, wherein the wavelength range is associated with a detection limited to a minimum radius of curvature along the fiber sensor; (b) reconstructing the shape of the fiber sensor (12) involving processing of interferometric signals received from the optical interrogation of the cores (14, 16, 18, 20), including reconstructing the shape of at least one out-of-range section along the fiber sensor (12) which is a section having a radius of curvature lower than the minimum radius of curvature, wherein reconstructing the shape of the at least one out-of-range section includes cal

Abstract: The present invention relates to an optical fiber sensor, comprising an optical fiber having embedded therein at least one fiber core (14, 16, 18, 20) extending along a length of the optical fiber, the at least one fiber core having a plurality of single fiber Bragg gratings (40, 42, 44) arranged in series along the at least one fiber core (14, 16, 18, 20), wherein each fiber Bragg grating (40, 42, 44) has a single reflection spectrum around a single reflection peak wavelength when interrogated with light in an unstrained state of the at least one fiber core (14, 16, 18, 20), wherein the reflection peak wavelengths of the single reflection spectra are different from fiber Bragg grating (40, 42, 44) to fiber Bragg grating (40, 42, 44) along the at least one fiber core. Also described is an optical system and a method of interrogating an optical fiber sensor.

Abstract: The present invention relates to an optical fiber sensor, comprising an optical fiber having embedded therein at least one fiber core (14, 16, 18, 20) extending along a length of the optical fiber, the at least one fiber core having a plurality of single fiber Bragg gratings (40, 42, 44) arranged in series along the at least one fiber core (14, 16, 18, 20), wherein each fiber Bragg grating (40, 42, 44) has a single reflection spectrum around a single reflection peak wavelength when interrogated with light in an untrained state of the at least one fiber core (14, 16, 18, 20), wherein the reflection peak wavelengths of the single reflection spectra are different from fiber Bragg grating (40, 42, 44) to fiber Bragg grating (40, 42, 44) along the at least one fiber core. Also described is an optical system and a method of interrogating an optical fiber sensor.

Abstract: The present invention relates to an optical shape sensing system, comprising an optical fiber sensor comprising an optical fiber having embedded therein a number of at least four fiber cores (1 to 6) arranged spaced apart from a longitudinal center axis (0) of the optical fiber, the fiber cores each having a resonance wavelength in response to light introduced into the fiber cores (1 to 6) in an unstrained state thereof. The system further comprises an optical interrogation unit (21) configured to interrogate the fiber cores (1 to 6) with light in a scan wavelength range including the resonance wavelengths of the fiber cores in an unstrained state of the fiber cores (1 to 6). The scan wavelength range is set such that a center wavelength of the scan wavelength range is decentered with respect to the resonance wavelength of at least one of the fiber cores (1 to 6).

Abstract: An optical fiber sensor includes an optical fiber. The optical fiber includes a cladding having a cladding refractive index, and a plurality of fiber cores embedded in the cladding and extending along a longitudinal axis of the optical fiber. The plurality of fiber cores include a first subset of at least one first fiber core and a second subset of at least one second fiber core. The at least one first fiber core has a first core refractive index different from the cladding refractive index and a first core radius in a direction transverse to the longitudinal axis. The at least one second fiber core has a second core refractive index different from the cladding refractive index and a second core radius transverse to the longitudinal axis. The second core refractive index and the second core radius differ from the first core refractive index and the first core radius such that a temperature sensitivity of the at least one second fiber core differs from the temperature sensitivity of the first fiber core.

Abstract: The present invention relates to an optical shape sensing system, comprising an optical fiber sensor comprising an optical fiber having embedded therein a number of at least four fiber cores (1 to 6) arranged spaced apart from a longitudinal center axis (0) of the optical fiber, the fiber cores each having a resonance wavelength in response to light introduced into the fiber cores (1 to 6) in an unstrained state thereof. The system further comprises an optical interrogation unit (21) configured to interrogate the fiber cores (1 to 6) with light in a scan wavelength range including the resonance wavelengths of the fiber cores in an unstrained state of the fiber cores (1 to 6). The scan wavelength range is set such that a center wavelength of the scan wavelength range is decentered with respect to the resonance wavelength of at least one of the fiber cores (1 to 6).

Abstract: 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.

Abstract: The present invention relates to an optical fiber sensor, comprising an optical fiber having embedded therein at least one fiber core (14, 16, 18, 20) extending along a length of the optical fiber, the at least one fiber core having a plurality of single fiber Bragg gratings (40, 42, 44) arranged in series along the at least one fiber core (14, 16, 18, 20), wherein each fiber Bragg grating (40, 42, 44) has a single reflection spectrum around a single reflection peak wavelength when interrogated with light in an untrained state of the at least one fiber core (14, 16, 18, 20), wherein the reflection peak wavelengths of the single reflection spectra are different from fiber Bragg grating (40, 42, 44) to fiber Bragg grating (40, 42, 44) along the at least one fiber core. Also described is an optical system and a method of interrogating an optical fiber sensor.

Abstract: An optical fiber sensor includes an optical fiber. The optical fiber includes a cladding having a cladding refractive index, and a plurality of fiber cores embedded in the cladding and extending along a longitudinal axis of the optical fiber. The plurality of fiber cores include a first subset of at least one first fiber core and a second subset of at least one second fiber core. The at least one first fiber core has a first core refractive index different from the cladding refractive index and a first core radius in a direction transverse to the longitudinal axis. The at least one second fiber core has a second core refractive index different from the cladding refractive index and a second core radius transverse to the longitudinal axis. The second core refractive index and the second core radius differ from the first core refractive index and the first core radius such that a temperature sensitivity of the at least one second fiber core differs from the temperature sensitivity of the first fiber core.

Abstract: The invention discloses an optical microscopy system (10) for stimulated emission depletion (STED) of an object (O). An optical element (6) is applied for focusing a first excitation (1) and a second depletion (2) beam on the object thereby defining a common optical path (OP) for both the first and the second beam. A phase modifying member (5) is inserted in the common optical path (OP), and the phase modifying member is optically arranged for leaving the wavefront of the first beam substantially unchanged, and for changing the wavefront of the second beam (2?) so as to create an undepleted region of interest (ROI) in the object. The first beam and the second beam have a common optical path because the phase modifying member adapts the wavefront or phase in such a way that it has no effect on the first beam, while on the second beam it gives rise to a wavefront, or phase change, resulting in a depleted region in the object (e.g. to the donut shaped spot) at the focal plane.

Abstract: The present invention relates to a method and system of obtaining a twist rate of a twist applied to an optical fiber (12) about a longitudinal axis of the optical fiber (12) at least in a part along a length of the optical fiber, the optical fiber (12) having a center core (16) extending along the length of the optical fiber (12) and at least one outer core (14, 18, 20) helically wound around the center core (16) with a spin rate.

Abstract: The present invention relates to a system (10) for guiding an instrument (12, 100, 100A, 100B, 112) in a body (14). The system (10) records an image where the instrument (12, 100, 100A,100B, 112) is identifiable and the instrument (12, 100, 100A, 100B, 112) records signals indicative of the type of tissue at the instrument (12, 100, 100A, 100B, 112). The system (10) determines the tissue type based on a signal from the instrument (12, 100, 100A, 100B, 112). The system (10) displays an image being a combined image of the body (14) and instrument (12, 100, 100A, 100B, 112) and an indication of tissue type at a position where the tissue type was determined. The present invention further relates to a method of displaying an image comprising tissue-type and instrument position in a body. The present invention further relates to an instrument and a software implemented method for being executed on a digital processor.

Abstract: The present invention relates to an optical shape sensing system for sensing a shape of a medical device (24), comprising an input polarization controller (12) for setting an input polarization state of an input light signal, at least one interferometer unit (18) for dividing said polarized input light signal into a device signal and a reference signal, guiding said device signal to be scattered within an optical fiber (19) inserted into said device (24) and coupling said scattered device signal with said reference signal to form an output light signal, and at least one measurement branch (39) comprising an output polarization controller arrangement (26) for setting an output polarization state of said output light signal, a polarizing beam splitter (30) for splitting said polarized output light signal into two signal portions, each being in a corresponding one of two signal portion polarization states, and a detector arrangement (35) comprising two detectors (32, 34), each for detecting a corresponding one o

Abstract: The present invention relates to a method and system of obtaining a twist rate of a twist applied to an optical fiber (12) about a longitudinal axis of the optical fiber (12) at least in a part along a length of the optical fiber, the optical fiber (12) having a center core (16) extending along the length of the optical fiber (12) and at least one outer core (14, 18, 20) helically wound around the center core (16) with a spin rate.

Abstract: The present invention relates to an optical shape sensing system for sensing a shape of a medical device (24), comprising an input polarization controller (12) for setting an input polarization state of an input light signal, at least one interferometer unit (18) for dividing said polarized input light signal into a device signal and a reference signal, guiding said device signal to be scattered within an optical fiber (19) inserted into said device (24) and coupling said scattered device signal with said reference signal to form an output light signal, and at least one measurement branch (39) comprising an output polarization controller arrangement (26) for setting an output polarization state of said output light signal, a polarizing beam splitter (30) for splitting said polarized output light signal into two signal portions, each being in a corresponding one of two signal portion polarization states, and a detector arrangement (35) comprising two detectors (32, 34), each for detecting a corresponding one o

Abstract: The present invention relates to a system (10) for navigating and positioning an instrument (12, 40, 112) in a body (14). The instrument (12, 40, 112) is detectable by the system (10) and the system (10) displays a view to an operator. The instrument (12, 40, 112) is adapted to identify tissue parameters. The system (10) is adapted to display an image being a combined image of the interior of a body (14) and an indication of the tissue parameter at the appropriate earlier locations. The present invention further relates to a method (44) including determining tissue parameters and displaying the parameters in an image of a body (14). The present invention further relates to a software implemented method (44) for being executed on a digital processor. The present invention further relates to an instrument (12, 40, 112).

Abstract: A clamp mechanism for fixation of an optical fiber (OSF) with optical shape sensing properties arranged for Optical Shape Sensing. A fixing element preferably with a circular cross section serves to engage with the optical fiber (OSF), and together with an additional fixing arrangement with a straight longitudinal portion arranged for engaging with the associated optical fiber (OSF), a fixation of a section of the optical fiber (OSF) is provided with the optical fiber (OSF) in a straight position. In some embodiments, the clamp mechanism can be implemented by three straight rods (R1, R2, R3) with circular cross section, e.g. with the same diameter being a factor of such as 6.46 times a diameter of the optical fiber (OSF). Hereby an effective fixation and straightening of the optical fiber (OSF) without disturbing strain can be obtained with a clamp mechanism which is easy to assemble and disassemble in practical applications e.g.

Abstract: There is presented an optical frequency domain reflectometry (OFDR) system (100) comprising a first coupling point (15) arranged for splitting radiation into two parts, so that radiation may be emitted into a reference path (16) and a measurement path (17). The system further comprises an optical detection unit (30) capable of obtaining a signal from the combined optical radiation from the reference path and the measurement path via a second coupling point (25). The measurement path (17) comprises a polarization dependent optical path length shifter (PDOPS, PDFS, 10), which may create a first polarization (PI) and a second polarization (P2) for the radiation in the measurement path, where the optical path length is different for the first and second polarizations in the measurement path. This may be advantageous for obtaining an improved optical frequency domain reflectometry (OFDR) system where e.g. the two measurements for input polarizations may be performed in the same scan of a radiation source.

Abstract: The present invention relates to an apparatus, a method and a computer program for determining a lipid-water ratio and a scattering parameter of a sample. In particular, the invention relates to an apparatus comprising a light source and a detector arranged to measure an optical parameter at various wavelengths, where the wavelengths are selected so that at two of the wavelengths the absorption coefficients for both water and lipids are substantially identical. This enables determination of a scattering parameter. A further measurement at a third wavelength enables determination of a water-lipid ratio. According to a specific embodiment, the light source and the detector are arranged in relation to an interventional device, so as to be able to examine a tissue in terms of lipid-water ratio and scattering during an intervention.

Abstract: The present invention relates to an optical sensing system (1) for determining the position and/or shape of an associated object (O), the system comprises an optical fibers (10) having one or more optical fiber cores (9) with one or more fiber Bragg gratings (FBG, 8) extending along the full length where the position and/or shape is be to determined of said object (O). A reflectometer (REFL, 12) measures strain at a number of sampling points along the optical fiber cores, and a processor (PROC, 14) determines the position and/or shape based on said measured strains from the plurality of optical fiber cores. The fiber Bragg grating(s) (FBG, 8) extends along the full length of said optical fiber cores (9), the fiber core having a spatially modulated reflection (r) along the said full length of the optical fiber core so that the corresponding reflection spectrum is detectable in said wavelength scan.