Optical fiber sensing system

Abstract

The invention provides a sensing system (1000) comprising a carrier arrangement (6000), a light source (100), n optical fiber sensors (200), a detector (500), and a control system (300), wherein: (A) the earner arrangement (6000) comprises a carrier (600); wherein the carrier (600) is selected from a wearable, a flexible human support, and bedding; (B) the light source (100) is configured to provide light source light (101); wherein the light source light (101) comprises one or more of UV radiation, visible radiation, and IR radiation; (C) the n optical fiber sensors (200) comprise a first optical fiber sensor (210) and a second optical fiber sensor (220), wherein the first optical fiber sensor (210) and the second optical fiber sensor (220) are comprised by the earner arrangement (6000); wherein the n optical fiber sensors (200) are configured in a light receiving relationship with the light source (100); (D) the detector (500) is functionally coupled to the n optical fiber sensors (200), and is configured to detect an optical response signal, wherein the optical response signal comprises one or more selected from the group of (i) a first optical response signal from the first optical fiber sensor (210), and (ii) a second optical response signal from the second optical fiber sensor (220); and (E) the control system (300) is configured to (a) determine at least two parameters based on the optical response signal, wherein the at least two parameters differ in parameter type, (b) derive from the at least two parameters information about one or more of: (i) a condition of the earner arrangement (6000), or a change thereof, (ii) a condition in an environment surrounding the earner arrangement (6000), or a change thereof, and (iii) a condition of a human in physical contact with the earner (600), or a change thereof, and (c) generate at least one output signal based on the information.

Description

[0001] Optical fiber sensing system

[0002] FIELD OF THE INVENTION

[0003] The invention relates to a sensing system. The invention further relates to a method for generating at least one output signal using the sensing system. Further, the invention relates to a system comprising the sensing system. Additionally, the invention relates to a use of the sensing system.

[0004] BACKGROUND OF THE INVENTION

[0005] Sensing systems are known in the art. For instance, WO2011091517A1 describes a method for modelling pressure exposure and / or the risk of pressure ulcer formation includes steps of using pressure sensors to derive pressure exposure or risk values and displaying the pressure exposure or risk values in a graphical manner to a user. Computer-implemented systems includes a pressure-sensing interface mat and components for implementing the steps of the methods.

[0006] US2014268099A1 describes a movement and expression sensor having a plurality of fiber Bragg gratings (FBG) disposed along the length of an optical fiber, and the optical fiber is placed in contact with a subject's skin surface. The sensors are interrogated for reflected wavelength, which is converted into a temperature or a strain. A series of such measurements can be made to determine the movement or position of the sensor location.

[0007] Li et al. (2024), Sensors, 24, 3602 describes the principles and technologies of various fiber sensors, including the Fiber Bragg Grating sensor, self-luminescent stretchable optical fiber sensor, and optic fiber Fabry-Perot sensor.

[0008] US2009185772Af describes a patient monitoring system including a plurality of diffraction gratings integrated along the length of an optical fiber, wherein the optical fiber and each grating are together configured to alter either the effective refractive index or grating periodicity of the respective grating at its corresponding location along the fiber in response to at least one desired external stimulus.

[0009] US2002041723A1 describes a body compatible fiber optic sensor probe. The probe includes at least one optical fiber and the fiber or fibers include at least one sensing region adapted and arranged such that the probe has simultaneously measurable respective optical properties that are responsive to respective different parameters within the body, suchproperties being dependent upon mechanical strain established in the fiber or fibers in response to said parameters.

[0010] CN115363540A describes a fiber optic monitoring unit for vital signs. A first fiber optic sensing element is arranged laterally to form a first sensing layer, and a second fiber optic sensing element is arranged to form a second sensing layer. The first and second sensing layers are stacked and the first and second fiber optic sensing elements are arranged crosswise. By utilizing the change in refractive index of the fiber optics under pressure, and the microscopic or macroscopic movements caused by the body's heartbeat, breathing, and physical activities, pressure is applied to the double-layered crosswise fiber optic sensing layer.

[0011] WO2016053398A1 describes systems of monitoring posture and vital signs. The system includes a cushion on which a user can sit. The cushion includes a first optical fiber sensor, a second sensor, and a first computing device. The system may further include a second computing device communicatively coupled to the first computing device and configured to receive sensor data from the first computing device. One or both of the first and second computing devices may operate to combine a signal indicative of the movement of the user with a signal indicative of the direction of movement of the user.

[0012] CN111150378A describes a non-invasive distributed fiber optic monitoring system and method for multiple vital signs during human sleep. The system includes a mattress, several vital sign fiber Bragg grating (FBG) sensors, a demodulator, and a host computer. The vital sign FBG sensors include several distributed temperature FBG sensors, distributed pressure FBG sensors, and distributed heart rate / respiration FBG sensors. All vital sign FBG sensors are fixedly installed in the filling material embedded between the mattress mesh and the fabric, maintaining the same depth. All vital sign FBG sensors are connected to the demodulator, and the output signal of the demodulator is transmitted to the host computer via a serial port to monitor the user's health status during sleep, including vital sign parameters such as heart rate, respiration, and body temperature.

[0013] Wu et al. (2023), Frontiers of Optoelectronics, 16:29 describes characteristics and sensing mechanisms of multimode sensing based on optical microcavities, multimode sensing methods such as multiparameter matrices and machine learning, and the applications of multimode microcavity sensing in different fields.

[0014] SUMMARY OF THE INVENTION

[0015] Pressure ulcers, also known as bedsores, pose a significant burden to both individuals and society. Despite increased awareness, their prevalence may remain largelyunchanged. Each year, approximately 3 million adults in the United States alone may be affected by pressure ulcers. These wounds result from prolonged pressure on the skin, restricting blood flow and causing tissue damage. The associated costs of care may continue to rise, impacting healthcare systems. Healthcare professionals (e.g. dermatologists) may play a crucial role in preventing pressure ulcers by identifying at-risk populations, implementing preventive strategies, and recognizing early changes to prevent skin breakdown. Addressing pressure ulcers may improve patient outcomes and reduce healthcare expenses.

[0016] Healthcare professionals currently employ various strategies to prevent pressure ulcers. One strategy involves regular skin assessments, focusing on areas prone to ulcers. Further, healthcare professionals may educate clients about early signs, preventive measures, and proper positioning. For hospitalized patients, who may be immobile, a turning schedule may be applied, wherein a patient is repositioned at regular intervals. In such cases, knowing the correct timing for turning a patient may play an important role in the prevention of pressure ulcers. Regular repositioning may help alternate body locations that are under pressure, maintain blood flow, and reduce the risk of skin breakdown. However, turning a patient too frequently or at inappropriate intervals may lead to friction and shear, potentially exacerbating ulcers and / or reducing skin integrity. Hence, healthcare professionals must balance the benefits of repositioning (especially in critical care scenarios) with the need to protect skin integrity. Individualized assessment and evidence-based guidelines guide decisions on when and how often to turn patients, ensuring their well-being and minimizing pressure ulcer risk. However, such individualized assessments may take time, which may not always be feasible in small or understaffed care facilities. Further, individualized turning schedules may be the result of a trial-and-error period, during which period the probability of developing pressure ulcers or other skin conditions may be increased. Apart from this, it may be difficult to educate a (personal) caregiver on proper techniques to identify and prevent pressure ulcers and / or skin conditions after discharge of the patient from the care facility, e.g. during a recovery period at home. A solution may be to use sensing systems, for instance based on pressure sensors, to reduce the time needed to determine an individualized turning schedule by measuring a time spent in a certain position and an absolute pressure exerted on the skin. Such sensing systems may be applied in hospital beds, for patients already suffering from a skin condition. However, it may be desirable to detect developing skin conditions before a patient experiences symptoms or discomfort, such that the development of said skin conditions may be halted before significant healthcare costs are incurred. Further, it may be desirable to provide a wearable and / or portable sensor system, which may also assist in other areas of a person’s health.Additionally, it may be desirable to measure multiple parameters at once, to facilitate a more complete assessment of a person’s condition. Hence, it is an aspect of the invention to provide an alternative sensing system, which preferably further at least partly obviates one or more of above-described drawbacks. The present invention may have as object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0017] According to a first aspect, the invention provides a sensing system comprising a earner arrangement, a light source, n optical fiber sensors, a detector, and a control system. The carrier arrangement may comprise a carrier. Especially, the earner may be selected from a (flexible) wearable, a flexible human support, and bedding. Further, the light source may be configured to provide light source light. Especially, the light source light may comprise one or more of UV radiation, visible radiation, and IR radiation. The n optical fiber sensors may comprise a first optical fiber sensor and a second optical fiber sensor. Further, the first optical fiber sensor and the second optical fiber sensor may be comprised by the earner arrangement. Additionally, the n optical fiber sensors may be configured in a light receiving relationship with the light source. The detector may be functionally coupled to the n optical fiber sensors, and may be configured to detect (in response to the light source light provided to one or more of the n optical fiber sensors) an optical response signal. In embodiments, the optical response signal may especially comprise one or more selected from the group of (i) a first optical response signal from the first optical fiber sensor, and (ii) a second optical response signal from the second optical fiber sensor. Further, the control system may be configured to determine at least two parameters based on the optical response signal. The at least two parameters may especially differ in parameter type. Additionally, the control system may be configured to derive from the at least two parameters information about one or more of: (i) a condition of the earner arrangement, or a change thereof, (ii) a condition in an environment surrounding the earner arrangement, or a change thereof, and (iii) a condition of a human (or animal) in physical contact with the earner, or a change thereof. Further yet, the control system may be configured to generate at least one output signal based on the information. Hence, in specific embodiments, the invention provides a sensing system comprising a earner arrangement, a light source, n optical fiber sensors, a detector, and a control system, wherein: (A) the earner arrangement comprises a carrier; wherein the earner is selected from a wearable, a flexible human support, and bedding; (B) the light source is configured to provide light source light; wherein the light source light comprises one or more of UV radiation, visible radiation, and IR radiation; (C) the n optical fiber sensors comprise a first optical fiber sensor and a second optical fiber sensor, wherein the first optical fiber sensor and the second optical fiber sensor are comprised by theearner arrangement; wherein the n optical fiber sensors are configured in a light receiving relationship with the light source; (D) the detector is functionally coupled to the n optical fiber sensors, and is configured to detect an optical response signal, wherein the optical response signal comprises one or more selected from the group of (i) a first optical response signal from the first optical fiber sensor, and (ii) a second optical response signal from the second optical fiber sensor; and (E) the control system is configured to (a) determine at least two parameters based on the optical response signal, wherein the at least two parameters differ in parameter type, (b) derive from the at least two parameters information about one or more of: (i) a condition of the earner arrangement, or a change thereof, (ii) a condition in an environment surrounding the earner arrangement, or a change thereof, and (iii) a condition of a human in physical contact with the earner, or a change thereof, and (c) generate at least one output signal based on the information. Such a sensing system may facilitate measuring and / or monitoring multiple parameters at the same time. Further, a sensing system comprising optical fiber sensors may have a relatively high sensitivity and accuracy. Additionally, optical fiber sensors may be relatively compact, thereby allowing for a high density of optical fiber sensors in the earner arrangement, facilitating a relatively high spatial resolution.

[0018] The earner may especially be a flexible human support. Further, the earner may comprise first and second sensing regions (see below), wherein the first optical fiber sensor may be configured embedded in the first sensing region, and the second optical fiber sensor may be configured embedded in the second sensing region. The first and second sensing regions may differ in a earner material of the earner (see below). Alternatively, the first and second sensing regions may comprise the same earner material, wherein one of the first and second sensing regions may be configured closer to a face of the earner than the other of the first and second sensing regions. Additionally or alternatively, the first and second sensing regions may be configured at least partially separated by a third carrier material.

[0019] The optical response signal may comprise the first and second optical response signal. Further, the control system may be configured to determine at least one, such as at least two, parameters based on the optical response signal. The at least two parameters may differ in parameter type. Especially, the parameter types may be selected from the group comprising a pressure, a temperature, a humidity, a strain, and a shear. Hence, in specific embodiments, the invention provides a sensing system comprising a earner arrangement, a light source, n optical fiber sensors, a detector, and a control system, wherein: (A) the earner arrangement comprises a earner; wherein the earner is a flexible human support; wherein the earner comprises a first sensing region and a second sensing region, wherein one or more applies of:(a) (i) the first sensing region comprises a first earner material, and the second sensing region comprises a second earner material different from the first carrier material; or (ii) one of the first sensing region and the second sensing region is configured closer to a face of the carrier than another of the first sensing region and the second sensing region, wherein the first sensing region and the second sensing region comprise a same carrier material; and (b) the first sensing region and the second sensing region are configured at least partially separated by a third earner material; (B) the light source is configured to provide light source light; wherein the light source light comprises one or more of UV radiation, visible radiation, and IR radiation; (C) the n optical fiber sensors comprise a first optical fiber sensor and a second optical fiber sensor, wherein the first optical fiber sensor and the second optical fiber sensor are comprised by the earner arrangement; wherein the first optical fiber sensor is configured embedded in the first sensing region, and wherein the second optical fiber sensor is configured embedded in the second sensing region; wherein the n optical fiber sensors are configured in a light receiving relationship with the light source; (D) the detector is functionally coupled to the n optical fiber sensors, and is configured to detect an optical response signal, wherein the optical response signal comprises (i) a first optical response signal from the first optical fiber sensor, and (ii) a second optical response signal from the second optical fiber sensor; and (E) the control system is configured to (a) determine (at least one, such as) at least two parameters based on the optical response signal, wherein the at least two parameters differ in parameter type, wherein the parameter types are selected from the group comprising a pressure, a temperature, a humidity, a strain, and a shear; (b) derive from the (at least one, such as) at least two parameters information about one or more of: (i) a condition of the earner arrangement, or a change thereof, and (ii) a condition of a human in physical contact with the carrier, or a change thereof, and (c) generate at least one output signal based on the information.

[0020] The sensing system may comprise a earner arrangement. Further, the earner arrangement may comprise a earner. In embodiments, the earner may be selected from (the group comprising) a (flexible) wearable, a flexible human support, and bedding. Hence, the earner may in embodiments be a (flexible) wearable. The (flexible) wearable may be selected from the group comprising an article of clothing (e.g. a shoe, gloves, a hat, a head band, etc.), an insole, a bandage, a brace, a (smart) watch, a belt, a (maternity) support belt, a sling, a (plaster or plastic) cast, and personal protective equipment (e.g. body armor, a mask, a lab coat, etc.). However, other (flexible) wearables are herein not excluded. Alternatively, the earner may be a flexible human support. The flexible human support may be selected from the group comprising a(n inflatable) pillow, a mattress (including an inflatable mattress), a mattress pad,a mattress protector, a gurney, a surgical or operating bed, a couch, a chair (cushion) or seat (e.g. a car seat), padding (e.g. on a wheelchair seat or armrest), a carpet, and a (fitness) mat. However, other flexible human supports are herein not excluded. For instance, the flexible human support may (also) be an insole. Yet, in embodiments, the earner may (comprise, such as especially) be bedding. The bedding may comprise one or more of a pillow case, a (fitted) sheet, a (top) sheet, a blanket, a duvet (cover), a comforter, and a quilt. However, other types of bedding may be possible, and are herein not excluded. In embodiments wherein the carrier comprises bedding, the earner arrangement may further comprise one or more of a mattress, a bed frame, a pillow, etc..

[0021] Further, the sensing system may comprise a light source. The term “light source” may in principle relate to any light source known in the art. In a specific embodiment, the light source may comprise a light emitting diode (LED). The term “light source” may relate to a plurality of (identical or different) light sources, such as 2-2000 light sources. Further, the term “light source” may also refer to a so-called chip-on-board (CoB) light source. The term “light source” may also refer to a chip scale package LED or a midpower package. Further, the light source may comprise one or more of mini LEDs and micro LEDs. The term “light source” may refer to a semiconductor light-emitting device, such as an LED, a resonant cavity LED, a vertical cavity laser diode (VCSELs), an edge emitting laser, etc.. The term “light source” may also refer to a superluminescent diode. Especially, the term “(solid state) light source” may refer to a semiconductor light source, such as an LED, a laser diode, a superluminescent diode, or a multi-junction diode. The term “laser diode” especially refers to a laser. Especially, the term “laser” may refer to a solid-state laser. In embodiments, the terms “laser” or “solid state laser” may refer to one or more of a semiconductor laser diode (e.g. GaN, InGaN, AlGalnP, AlGaAs, InGaAsP, lead salt), a VCSEL, a quantum cascade laser, a hybrid silicon laser, etc.

[0022] Hence, the light source may comprise any light source known in the art. Especially, the light source may comprise a laser light source. Alternatively, the light source may comprise (one or more of) a LED, a laser diode, a superluminescent diode, and a (stacked) multi-junction diode. Further, the light source may be configured to provide light source light. The light source light may comprise one or more of UV radiation, visible radiation, and IR radiation. The term “UV radiation” or “ultraviolet radiation” may especially refer to light having one or more wavelengths selected from the range of 190-380 nm, such as from the range of 200-380 nm. The terms “visible radiation” may refer to light having one or more wavelengths in the range of 380-780 nm. Further, the term “IR radiation” or “infrared radiation” may refer to light having one or more wavelengths selected from the range of 780-3000 nm, such as 780-2000 nm. In specific embodiments, the light source light may comprise one or more of UV radiation, visible radiation, and IR radiation. In specific embodiments, the light source light may (at least) comprise light having a wavelength selected from the range of > 800 nm, such as from the range of > 1200 nm, especially from the range of > 1400 nm. The light source light may comprise light having a wavelength selected from the range of 750-950 nm, such as from the range of 800-900 nm, especially from the range of 825-875 nm. Further, the light source light may comprise light having a wavelength selected from the range of WOOHOO nm, such as from the range of 1250-1350 nm, especially from the range of 1275-1325 nm. Further, the light source light may comprise light having a wavelength selected from the range of 1450-1650 nm, such as from the range of 1500-1600 nm, especially from the range of 1525-1575 nm. The light source may be an adjustable light source. Further, the control system may be configured to control the light source. Especially, the control system may be configured to control one or more of an intensity of the light source light and a wavelength (range) of the light source light. Further, the light source may be configured to provide light comprising a first wavelength (range) to the first optical fiber sensor, and to provide light comprising a second wavelength (range) to the second optical fiber sensor. In embodiments, the light source light may be configured to emit a relatively broad (continuous) spectrum of light (e.g. having a bandwidth of > 200 nm), wherein the light source may comprise one or more optical filters, wherein each optical fiber sensor may be configured in a light receiving relationship with at least one optical filter, and wherein the one or more optical filters may be configured to transmit light in a narrow wavelength range (e.g. a band of < 10 nm) to the optical fiber sensor, wherein each optical filter may be configured to transmit light in a different wavelength range. Especially, the light source may be configured to provide identical or different light source light to each of (or different subsets of) the n optical fiber sensors.

[0023] Alternatively, as indicated above, the light source may refer to, or comprise, a plurality of light sources. Hence (or alternatively), in embodiments, the sensing system may comprise a plurality of light sources. In such embodiments, each of the n optical fiber sensors may be configured in a light receiving relationship with a different (subset of) light source(s) of the plurality of light sources. In embodiments, the plurality of light sources may (each) be configured to generate light source light having the same spectral power distribution. Alternatively, at least two of the plurality of light sources may be configured to generate light source light having a different spectral power distribution (wherein said at least two light sources may be configured in a light receiving relationship with the same or different opticalfiber sensors). Further yet, all of the plurality of light sources may be configured to generate light source light having a different spectral power distribution.

[0024] The sensing system may comprise n optical fiber sensors. In embodiments, n may be selected from the range of > 2, such as from the range of > 3, especially from the range of > 4. Further, n may be selected from the range of > 5, such as from the range of > 7, especially from the range of > 10. Additionally or alternatively, n may be selected from the range of < 600, such as from the range of < 500, especially from the range of < 400. Hence, in embodiments, n may be selected from the range of 2-600, such as from the range of 3-500, especially from the range of 4-400. Further, n may be selected from the range of 5-600, such as from the range of 7-500, especially from the range of 10-400. The n optical fiber sensors may be arranged in an array. The array may be regular, random, or quasi random. In embodiments, the array of optical fiber sensors may be a regular 2D array. Alternatively, the array of optical fiber sensors may be a 3D array. Further, the n optical fiber sensors may be arranged in two 2D arrays. The array may be an irregular ring tessellation array, a phyllotaxis tessellation array, a rotated hexagonal tessellation array, a Hirschhom tessellation array, a polycrystal tessellation array, a spiral tessellation array, and a self-avoiding random tessellation array. Alternatively, and especially, the array may be a regular array. Especially, the array may be an n*m array, wherein n and m may each be individually selected from the range of > 2. In embodiments, the regular array may have one or two constant pitches.

[0025] In embodiments, the n optical fiber sensors may be configured with a certain density in the array. Especially, the array of n optical fiber sensors may comprise (i.e., have a density of) > 150 optical fiber sensors per square meter, such as > 200 optical fiber sensors per m2, especially > 250 optical fiber sensors per m2. Further, the array of n optical fiber sensors may comprise > 500, such as > 1000, especially > 1300, like > 1500, optical fiber sensors per m2. Additionally or alternatively, the array of n optical fiber sensors may comprise < 21000, such as < 20500, especially < 20000, optical fiber sensors per m2. Further, the array of n optical fiber sensors may comprise < 10000, such as < 6000, especially < 5000, like < 4000, optical fiber sensors per m2. Hence, the array of n optical fiber sensors may comprise 150-21000 optical fiber sensors per m2, such as 200-20500 optical fiber sensors per m2, especially 250-20000 optical fiber sensors per m2. Further, the array of n optical fiber sensors may comprise 500-10000 optical fiber sensors per square meter, such as 1000-6000 optical fiber sensors per m2, especially 1300-5000 optical fiber sensors per m2, like 1500-4000 optical fiber sensors per m2. The n optical fiber sensors may be arranged with the same density throughout the array. Alternatively, the density of optical fiber sensors in the array may vary throughout the array.Especially, the sensing system, such as especially the array of optical fiber sensors, may be configured to be placed in (direct or indirect) contact with a human (or animal), wherein the density of optical fiber sensors in the array may be higher at locations where the bones of the human (or animal) may be located close to the skin. For instance, the array of optical fiber sensors may be configured embedded in a earner such as a mattress or mat, wherein a density of optical fiber sensors in the array may be higher at locations configured in contact with one or more of the heels, the sacral regions, the spine, and the skull. As such locations may have a relatively higher risk of developing pressure ulcers, a relatively high spatial resolution and / or relatively more accurate measurements may be desired.

[0026] Hence, the n optical fiber sensors may be arranged in one or more (2D) arrays. Especially, the n optical fiber sensors may be arranged in at least two arrays (each having a density as described above). As such, a first sensor array of optical fiber sensors may be configured embedded in the first sensing region, such as in the first sensing layer (see below). Further, as such, a second sensor array of optical fiber sensors may be configured embedded in the second sensing region, such as in the second sensing layer (see below). The first sensor array may comprise nl optical fiber sensors, and the second sensor array may comprise n2 optical fiber sensors. Especially, each of nl and n2 may be selected from the range of 1 to n-1, such as from the range of 0.1 *n to 0.9*n, especially from the range of 0.3*n to 0.7*n. In embodiments, nl = n2 = 0.5*n may apply. The one or more (2D) arrays of optical fiber sensors may be configured in a single plane (in the earner). Alternatively, the one or more, such as especially the first and second, (sensor) arrays may be configured in separate planes (in the earner). In such embodiments, the first and second sensor arrays may especially be configured spatially separated along at least a direction perpendicular to (a plane of) the first (and / or second sensor) array.

[0027] The n optical fiber sensors may (each comprise an optical fiber sensor type, wherein the optical fiber sensor type may for each of the n optical fiber sensors) be individually selected from the group comprising a fiber Bragg grating, a microbend sensor, a polarimetric sensor, a distributed temperature sensor, a long-period fiber grating, a tapered optical fiber interferometer, a Fabry-Perot interferometer fiber, a fiber-optic Mach-Zehnder interferometer, a fiber-optic Michelson interferometer, a fiber-optic Sagnac interferometer, a surface plasmon resonance-based fiber-optic sensor, a fluorescence-based fiber-optic probe, a light diffuser-integrated optical fiber sensor, a multi-mode interference sensor, and a hollow fiber sensor. In embodiments, the n optical fiber sensors may each comprise the same optical fiber sensor type. Further, each of the n optical fiber sensors may be identical. Alternatively, at least two of then optical fiber sensors may differ, such as be of a different optical fiber sensor type. The n optical fiber sensors may comprise the first optical fiber sensor and the second optical fiber sensor. The first optical fiber sensor may be of the same optical fiber sensor type as the second optical fiber sensor. Further, the first optical fiber sensor may be identical to the second optical fiber sensor. Alternatively, the first optical fiber sensor may be of a different optical fiber sensor type as the second optical fiber sensor. Hence, in specific embodiments, the first optical fiber sensor and the second optical fiber sensor may be individually selected from the group comprising a fiber Bragg grating, a microbend sensor, a polarimetric sensor, a distributed temperature sensor, a long-period fiber grating, a tapered optical fiber interferometer, a Fabry-Perot interferometer fiber, a fiber-optic Mach-Zehnder interferometer, a fiber-optic Michelson interferometer, a fiber-optic Sagnac interferometer, a surface plasmon resonance-based fiberoptic sensor, a fluorescence-based fiber-optic probe, a light diffuser-integrated optical fiber sensor, a multi-mode interference sensor, and a hollow fiber sensor. Such optical fiber sensors may have a relatively high sensitivity and / or accuracy. Further, such optical fiber sensors may be relatively compact. Additionally or alternatively, such optical fiber sensors may be relatively durable and / or chemically inert.

[0028] An optical fiber sensor may comprise, such as be based on, an optical fiber (part). Generally, an optical fiber may comprise a (transparent) waveguide. The (transparent) waveguide may comprise one or more of plastic, glass, silica, and air. Further, the waveguide may comprise a waveguide core and a waveguide cladding, wherein the waveguide cladding may have a lower refractive index than the waveguide core. Light may be coupled into the optical fiber, wherein the light may propagate through the waveguide (core) due to total internal reflection (TIR). Yet, at a boundary between two materials having a different refractive index (e.g. at a boundary between the waveguide core and cladding), light may be emitted from the waveguide. Especially, the optical fiber, such as especially the waveguide, may have a critical angle (0C), wherein light incident on the boundary with an angle < 9Cmay be (refracted and) emitted from the waveguide, and wherein light incident on the boundary with an angle > 9Cmay be reflected back into the waveguide core through TIR. The critical angle of an optical fiber may be (at least partially) determined by a difference between the refractive index of the waveguide core and the refractive index of the waveguide cladding, as is known to the person skilled in the art. Hence, an optical fiber sensor may comprise at least part of an optical fiber. Here below, different (types of) optical fiber sensors will be briefly explained:

[0029] A fiber Bragg grating (FBG) may refer to an optical fiber, wherein the waveguide core comprises a distributed Bragg reflector (“DBR”) (along a segment of thewaveguide core). As is known in the art, a DBR may comprise a plurality of layers of alternating materials having different refractive indices. Hence, a DBR may provide a periodic variation in the refractive index of the waveguide core (in a propagation direction of the light source light through the waveguide core). As such, the DBR may be configured to reflect light in a first wavelength range, and transmit light outside of the first wavelength range. The first wavelength range may be determined by Bragg’s law, and may comprise those wavelengths for which the following (Bragg) condition is satisfied: X = 2*neff*A, wherein neff is the effective refractive index of light in the optical fiber, and wherein A is the grating period of the DBR. In embodiments, one or more of neff and A may be at least partially determined by one or more of a (current) temperature, pressure, humidity, strain, and shear on or around the FBG. Hence, changing one or more of these conditions may result in a shift in the first wavelength range. Hence, by measuring a wavelength of the light reflected and / or transmitted by the FBG, one or more of a temperature, pressure, humidity, strain, and shear may be determined. In embodiments, the FBG may comprise a uniform grating, wherein the refractive index modulation has a constant period along the DBR. Alternatively, the FBG may comprise a chirped FBG, wherein the refractive index modulation (linearly) increases or decreases along the DBR. An FBG may be a type of diffraction grating, formed in an optical fiber (core).

[0030] A microbend sensor may be based on mechanical deformations in a multimodal optical fiber. A section of a multimodal optical fiber is placed in a micro-bending modulator structure (MBMS), wherein the MBMS may be configured to apply a mechanical deformation to the optical fiber. Especially, the MBMS may comprise two complementary plates or diaphragms, wherein the optical fiber may be placed between the complementary plates or diaphragms, and wherein each plate or diaphragm may comprise one or more of a saw-tooth pattern, a wave pattern, or a sinusoidal pattern. The two complementary plates or diaphragms of the MBMS may be configured to move with respect to each other in response to an external stimulus (e.g. a pressure), such as move closer to each other, and / or slide alongside each other. The movement of the MBMS may alter a shape of the optical fiber in between the complementary plates or diaphragms. Especially, the shape of the optical fiber may start to increasingly mimic the (corrugated) pattern of the complementary plates or diaphragms upon a decrease in the distance between the complementary plates or diaphragms. Hence, the optical fiber may be bent more or less, depending on the relative positions of the complementary plates or diaphragms. Bending of the optical fiber may lead to a loss in the intensity of the light travelling along the optical fiber, as the bends may facilitate the outcoupling of light. Hence, ameasurement of the intensity of the light transmitted through the optical fiber may thus facilitate measuring (a magnitude of) the external stimulus.

[0031] A polarimetric sensor may be based on an optical fiber comprising a birefringent material. Light having a known polarization (distribution) may be injected into the optical fiber, wherein the birefringent material may split the light into two beams having orthogonal linear polarizations, and wherein both beams may propagate through the birefringent material at different speeds. At the end of the polarimetric sensor, a detector may be used to detect (the intensity of) light transmitted through the birefringent material and having a specific linear polarization. Further, multiple detectors may be used, wherein each detector detects the intensity of light having a certain linear polarization. As the polarization of the light travelling through the birefringent material may change in response to an external stimulus, measuring the intensity of light having a specific linear polarization may facilitate measuring (a magnitude of) the external stimulus.

[0032] A distributed temperature sensor may comprise an optical fiber functionally coupled with a (laser) light source and a light detector. A pulse of (laser) light is injected into the optical fiber, and may interact with local imperfections and / or local variations in the refractive index along the optical fiber, thereby causing back-scattering (especially Raman scattering) of the light. Further, interactions between the light and the optical fiber material may shift the wavelength distribution of the back-scattered light, wherein part of the reflected light may undergo a shift to longer wavelengths (referred to as the Stokes signal), and part of the reflected light may undergo a shift to shorter wavelengths (referred to as the anti-Stokes signal). The intensity of the anti-Stokes signal may, unlike the intensity of the Stokes signal, be highly dependent on the (local) temperature at the point of reflection. Hence, by measuring a ratio between the intensity of the Stokes signal and the anti-Stokes signal, the temperature at the point of reflection may be determined. Further, the travel time of the reflected (light) signal may be used to determine a point of reflection. Hence, a distributed temperature sensor may provide a temperature map of the temperature along the length of the optical fiber.

[0033] A long-period fiber grating may be similar to a fiber Bragg grating (FBG), in that a long-period fiber grating may comprise an optical fiber having a periodic modulated refractive index in the waveguide core. However, in a long-period fiber grating, the period (of the refractive index modulation) is larger, such as especially on a millimeter scale. With a long-period fiber grating, the light transmitted by the long-period fiber grating may be measured, as a long-period fiber grating may show limited backward reflection in the waveguide core.A tapered optical fiber interferometer may comprise an optical fiber, wherein, over a small length of the optical fiber, the optical fiber may be stretched out, thereby creating an optical fiber region having a very small diameter (compared to the remainder of the optical fiber). Due to the small diameter of the optical fiber, the waveguide cladding may act as a (new) waveguide core for the propagation of light through the waveguide. Hence, for a tapered optical fiber interferometer, the difference between the refractive index of the waveguide cladding and the refractive index of an exterior (coating) of the optical fiber may determine the 9C. For a tapered optical fiber interferometer sensor, a stimuli-responsive layer may be applied to the exterior of the tapered section of the optical fiber, to function as the new “waveguide cladding”. A refractive index of this stimuli-responsive layer may change in response to an external stimulus (e.g. temperature), thereby changing the critical angle of (and therefore the percentage of light transmitted by) the tapered optical fiber interferometer.

[0034] A Fabry-Perot interferometer fiber (FPIF) may refer to an optical fiber comprising two parallel reflecting surfaces isolated by a certain distance. The parallel reflecting surfaces may be constructed inside (intrinsic FPIF) or outside (extrinsic FPIF) of the fiber, wherein for an extrinsic FPIF the parallel reflecting surfaces may define a cavity comprising a(n external) medium (e.g. an air cavity). The transmission and reflection spectra of an FPIF may depend on the optical phase difference (OPD) between two interfering light beams: a first beam reflected at the first reflecting surface, and a second beam transmitted by the first reflecting surface and reflected at the second reflecting surface. Further, the OPD may depend on the distance between the two reflecting surfaces, as well as the refractive index of the medium between the two reflective surfaces. Due to e.g. strain on the FPIF (e.g. by bending of the optical fiber), the distance between the two reflecting surfaces may change, leading to a change in the OPD, and thereby a change in the transmission and reflection spectra of the FPIF.

[0035] A fiber-optic Mach-Zehnder interferometer (FOMZI) may comprise a reference optical fiber (part), a sensing optical fiber (part), a beam splitter, and a beam combiner. The beam splitter may divide a beam of light over the sensing optical fiber (part) and the reference optical fiber (part), wherein the reference optical fiber (part) may have a fixed optical path length, and wherein the sensing optical fiber (part) may have an optical path length depending on one or more external stimuli. The beam combiner may combine the beams of light downstream of the reference and sensing optical fiber(s) (parts), thereby allowing the beams of light to interfere with one another in a manner depending on the difference in optical path length and / or phase, wherein the resulting interference spectrum may provide information regarding (the intensity of) the one or more external stimuli. Several options may be availableto design the FOMZI, such as: (i) providing a separate optical fiber for the reference and sensing optical fibers, (ii) introducing two long-period gratings in an optical fiber, wherein a first grating may act as a beam splitter, and wherein a second grating may act as a beam combiner, (iii) placing a small sensing section along an optical fiber with a (minute) lateral offset with respect to parts of the optical fiber before and after the sensing section, wherein the beam of light may be split and recombined at the boundaries between the optical fiber and the sensing section, and (iv) providing two tapered sections having a very small diameter spatially separated along an optical fiber, wherein the tapered sections may act as beam splitter and beam combiner.

[0036] A fiber-optic Michelson interferometer (FOMI) may be similar to a FOMZI, in that a beam of light is split into a reference path and a sensing path. However, a FOMZI may be operated in the transmission mode, whereas a FOMI may be operated in the reflection mode. Especially, in a FOMI, the beam of light may be split into a reference beam and a sensing beam, wherein both beams may be reflected (e.g. by an intrinsic or extrinsic mirror) before being re-combined. Further, a FOMI may have a similar design as a FOMZI, with the exception that the beam splitter may also act as the beam combiner for the reflected beams.

[0037] A fiber-optic Sagnac interferometer (FOSI) may comprise a beam redirection element configured along an optical fiber, and an optical fiber loop functionally coupled to the beam redirection element. The optical fiber loop may further comprise a sensing section and (optionally) one or more polarization controllers, wherein the sensing section may comprise a birefringent material. A beam of light may be provided to the beam redirection element, wherein the beam redirection element may be configured to split the beam of light into two beams travelling in opposite directions along the optical fiber loop. The two beams may be recombined at the beam redirection element, wherein the beams may undergo interference depending on a birefringent coefficient of the sensing section, wherein the birefringent coefficient may be influenced by an external stimulus to provide a stimulus-dependent interference pattern.

[0038] A surface plasmon resonance-based fiber-optic sensor (SPRFS) may be based on one or more of planer surface plasmons and localized surface plasmons. An SPRFS may comprise an optical fiber, wherein in part of the optical fiber the waveguide cladding is removed, and the waveguide core is coated with a thin layer of plasmonic material (e.g. silver or gold). The plasmonic section of the fiber is exposed to an external stimulus (e.g. an analyte solution), or coated with a coating having a stimulus-dependent refractive index. (Polychromatic) light may be introduced into the optical fiber, such that evanescent wavesoriginate at the interface between the waveguide core and the plasmonic material, thereby inducing surface plasmons at said interface. The transmission (or reflection) spectrum of the SPRFS may display a (sharp) dip at the resonance wavelength of the sensor. Upon modulation in the refractive index of the external of the optical fiber due to (a change in) the external stimulus, a shift in the resonance wavelength is observed.

[0039] A fluorescence-based fiber-optic probe may be based on Forster resonance energy transfer (FRET). FRET is a process in which a donor fluorophore is excited into an excited state, subsequently transfers energy to an acceptor fluorophore (in the ground state) to fall back to the ground state, and wherein the acceptor fluorophore falls back to the ground state under the emission of light. As is known to the person skilled in the art, the efficiency of FRET (i.e., the ratio between a fluorescence intensity from the donor fluorophore and from the acceptor fluorophore, or an absolute intensity of the fluorescence of the acceptor fluorophore) may be dependent on the distance between (and concentrations of) the donor and acceptor fluorophore. A fluorescence-based fiber-optic probe may comprise an optical fiber comprising a donor fluorophore, an acceptor fluorophore, and a recognition agent, wherein the recognition agent may be configured to adjust a distance between the donor fluorophore and the acceptor fluorophore in response to an external stimulus. In such embodiments, the FRET efficiency in the optical fiber may be used for sensing. Alternatively, a fluorescence-based fiber-optic probe may be based on an optical fiber comprising a single fluorophore, wherein the fluorophore has an emission and / or absorption spectrum, or a fluorescence lifetime, which may shift due to (changes in) an external stimulus. In such embodiments, the emission and / or absorption spectrum, or the fluorescence lifetime, of the optical fiber may be measured to sense (a magnitude of) the external stimulus.

[0040] A light diffusor-integrated optical fiber sensor may be based on a stimuli-responsive hydrogel, which may be imprinted with a light-diffusing microstructure. The stimuli-responsive hydrogel may be chemically attached to a distal end of an optical fiber. Further, the light-diffusing microstructure may scatter an incident light beam (guided through the optical fiber) at different angles in both the forward direction and backward direction, thereby facilitating the projection of a diffused light spot on an imaging plane. The stimuli-responsive hydrogel may undergo a volumetric shift upon interaction with the target stimulus (e.g. an analyte, a temperature, a pressure, etc.), which may induce a change in the refractive index and dimensions of the light-diffusing microstructure, thereby inducing a change in the scattering efficiency and / or the angle of the scattered light. Hence, the intensity and / ordistribution of the transmitted and / or reflected light may be used to sense (a magnitude of) the external stimulus.

[0041] A multi-mode interference sensor (MMI) comprises a multi-mode optical fiber, wherein the light may propagate through the fiber via more than one propagation mode. Light may be enter and exit the MMI via respectively (single-mode) lead-in and lead-out optical fibers. Further, the light travelling through the different propagation modes may interfere with each other, in a manner dependent on one or more external stimulus. Hence, sensing may occur by detecting an interference pattern of the light (collected) in the lead-out optical fiber.

[0042] A hollow fiber sensor may comprise an optical fiber wherein the waveguide core may comprise one or more air pockets. The one or more air pockets may be filled with an analyte of interest, or with a stimulus-responsive medium, such that, in response to a change in analyte concentration or the selected stimulus, one or more of (i) a percentage of light reflected or transmitted through the optical fiber, (ii) a peak wavelength of the reflected or transmitted light, and (iii) a distribution of the reflected or transmitted light may change.

[0043] In embodiments, the first optical fiber sensor may especially comprise, such as be, a fiber Bragg grating (FBG). Additionally or alternatively, the second optical fiber sensor may comprise, such as be, a fiber Bragg grating (FBG). Hence, in specific embodiments, the first optical fiber sensor may comprise a fiber Bragg grating, and the second optical fiber sensor may comprise a fiber Bragg grating. FBGs may facilitate measuring several parameters (simultaneously), and may therefore be relatively versatile. Further, FBGs may have a relatively high sensitivity, and / or may be relatively accurate. In embodiments, (a first subset of) the n optical fiber sensors (such as the first and second optical fiber sensors) may be comprising by the same optical fiber. Hence, the sensing system may comprise a plurality of diffraction gratings integrated along the length of an optical fiber.

[0044] The n optical fiber sensors, such as especially the first optical fiber sensor and the second optical fiber sensor, may be comprised by the carrier arrangement. Further, the first optical fiber sensor and the second optical fiber sensor may be configured on or in physical contact with the carrier. In embodiments, the earner may comprise the first optical fiber sensor and the second optical fiber sensor. Especially, the first optical fiber sensor and the second optical fiber sensor may be configured embedded in the earner. Further, the n optical fiber sensors may be configured embedded in the carrier. As indicated above, the earner may comprise a flexible human support. Alternatively, the earner may comprise a flexible skin support. The flexible human support (and / or the flexible skin support) may be selected from the group comprising a pillow, a mattress, a mattress pad, a mattress protector, a gurney, acouch, a chair (cushion), a beanbag, a carpet, an insole, and a (fitness) mat. Especially, the flexible human support (and / or the flexible skin support) may be a mattress. Further, the earner may comprise a first sensing region and a second sensing region. In embodiments, the first optical fiber sensor may be configured embedded in the first sensing region. Further, the second optical fiber sensor may be configured embedded in the second sensing region. In embodiments, the first sensing region may comprise a first earner material, and the second sensing region may comprise a second earner material, different from the first material. That is, the first and second optical fiber sensors may be configured embedded in different materials. In embodiments, one of the first sensing region and the second sensing region may at least partially enclose the other of the first sensing region and the second sensing region. Alternatively, the first and second sensing regions may be configured at least partially (spatially) separated by a third earner material, wherein the first and second sensing regions may comprise the same or different earner materials. Hence, in embodiments, the first and second sensing regions may comprise the same carrier material (and may not be separated by a third carrier material). In such embodiments, during operation of the sensing system, one of the first and second sensing regions may be configured closer to a (sur)face of the earner than another of the first and second sensing regions. Alternatively, the first and second sensing regions may be configured equidistant from the (sur)face of the carrier, wherein the first and second sensing regions may be configured spatially separated along the (sur)face of the earner. Further, the first and second sensing regions may be spatially separated in at least two (orthogonal) directions, wherein a first direction may be perpendicular to the (sur)face of the carrier, and wherein a second direction may be parallel to the (sur)face of the carrier. Yet, the first and second sensing regions may comprise different carrier material (such as the first and second earner material, respectively), wherein one may apply of: (i) (during operation of the sensing system,) one of the first and second sensing regions may be configured closer to a (sur)face of the earner than another of the first and second sensing regions, and (ii) the first and second sensing regions may be configured spatially separated along the (sur)face of the earner. Hence, the first and second sensing regions may refer to discrete (or distinct) regions within the earner, yet may also refer to “virtual” or “imaginary” regions within the earner. In specific embodiments, the earner may comprise a flexible human support, wherein the earner may comprise a first sensing region and a second sensing region, wherein the first optical fiber sensor may be configured embedded in the first sensing region, and wherein the second optical fiber sensor may be configured embedded in the second sensing region. Such a first and second sensing region may facilitate that a response of the first and second optical fiber sensor to thesame stimulus may be different. Hence, such a first and second sensing region may facilitate more easily decoupling at least two parameters from the optical signal.

[0045] In embodiments, each of the first, second, and third earner material may be individually selected from the group comprising a fabric, a foam, (natural or synthetic) batting or down, a gel, a particulate substrate, an open-structured material, a leather, a (natural or synthetic) rubber, and combinations thereof. In embodiments, the fabric may be a natural or synthetic fabric, such as comprising one or more of cotton, silk, jute, wool, linen, hemp, polyester, nylon, viscose, and elastane. Further, the foam may comprise one or more of foam latex (or “latex foam rubber”), polyurethane foam (e.g. memory foam), and latex-like foam. The (natural or synthetic) batting or down may comprise one or more of cotton (fibers), wool (fibers), bamboo (fibers), silk (fibers), polyester (fiber(fill)), goose down, duck down, eiderdown, and Muscovy down. Further, the gel may comprise gel beads, a homogeneous gel layer, or gel beads embedded in a foam (such as one or more of the foams described above. The particulate substrate may comprise one or more of (dried) beans, (dried) lentils, (dried) flaxseed, (dried) cherry pits, (dried) rice, sand, (dried) (buck)wheat, polyvinyl (chloride) particles, expanded polystyrene particles, expanded polypropylene particles, and shredded foam particles. Further, the open-structured material may comprise one or more of a (pocket) spring, a (metal, textile, and / or fiber) mesh, and a foam structure comprising one or more of pores, channels, and (air) pockets.

[0046] Would the first and second sensing region comprise the same earner material, the carrier material may be the first carrier material. Would the first and second earner material differ, the first and second earner materials may differ in the type of material. For instance, the first carrier material may be a fabric, and the second earner material may be a foam. Yet, would the first and second earner materials differ, the first and second earner materials may comprise the same type of material (e.g. a foam), yet may differ in the (specific) material. For instance, the first earner material may comprise foam latex, and the second earner material may comprise polyurethane foam. Yet further, would the first and second earner materials differ, the first and second earner materials may comprise the same material, yet the first and second carrier materials may differ in one or more properties of the material. For instance, (both) the first and second earner materials may comprise polyurethane foam, wherein a density of the polyurethane foam in the first earner material may be higher than a density of the polyurethane foam in the second earner material. Hence, the first and second earner material may differ in one of: (i) the type of material, (ii) the material, and (iii) the properties of the material. Similarly, would two (or more) of the first, second, and third earner differ, said earnermaterials may differ in one of: (i) the type of material, (ii) the material, and (iii) the properties of the material. In embodiments, the third earner material may be comprised by a third region, wherein the third region may be configured between the first sensing region and the second sensing region. The third region may be free from optical fiber sensors, yet may also comprise one or more optical fiber sensors. Hence, the third region may be a third sensing region.

[0047] As indicated above, the first and second sensing regions may be distinct regions. Especially, the first sensing region may be a first sensing layer within the earner, wherein the first optical fiber sensor may be configured embedded in the first sensing layer. Further, the second sensing region may be a second sensing layer within the earner, wherein the second optical fiber sensor may be configured embedded in the second sensing layer. In embodiments, the n optical fiber sensors may comprise a first subset of optical fiber sensors and a second subset of optical fiber sensors, wherein the first subset may be configured embedded in the first sensing layer (as the first sensor array), and wherein the second subset may be configured embedded in the second sensing layer (as the second sensor array). Hence, the earner may comprise a layer stack. The earner (such as especially the layer stack) may comprise the first sensing layer, the second sensing layer, and a (human) skin contacting face. The (human) skin contacting face may be the face of the earner, which during use of the earner may be configured in (direct or indirect) contact with the skin of a human (or animal) placed on the earner. In embodiments, the first sensing layer may comprise the (human) skin contacting face. Alternatively, the second sensing layer may comprise the (human) skin contacting face. That is, the (human) skin contacting face may be comprised by either the first sensing layer or the second sensing layer. Further, during use of the sensing system, such as especially the carrier, the one of the first sensing layer and the second sensing layer comprising the (human) skin contacting face may be configured closer to the (human) skin than the other of the first sensing layer and the second sensing layer (not comprising the skin contacting face). Especially, (the layer stack comprising) the first sensing layer and the second sensing layer may be configured stacked in a direction parallel to a normal to the (human) skin configured in contact with the carrier (during use of the earner). Alternatively, (the layer stack comprising) the first sensing layer and the second sensing layer may be configured stacked in a direction parallel to the (human) skin configured in contact with the earner (during use of the earner). In such embodiments, both the first sensing layer and the second sensing layer may comprise the (or a) skin contacting face. Yet, especially, one of the first sensing layer and the second sensing layer may comprise the skin contacting face. Hence, in specific embodiments, (A) the earner may comprise a flexible human support, wherein the earner may comprise a first sensing layer,a second sensing layer, and a skin contacting face; wherein the skin contacting face may be comprised by either the first sensing layer or the second sensing layer; and (B) the first optical fiber sensor may be configured embedded in the first sensing layer, and the second optical fiber sensor may be configured embedded in the second sensing layer. Further, in specific embodiments, (A) the earner may comprise a flexible skin support, wherein the earner may comprise a first sensing layer, a second sensing layer, and a skin contacting face; wherein the skin contacting face may be comprised by either the first sensing layer or the second sensing layer; and (B) the first optical fiber sensor may be configured embedded in the first sensing layer, and the second optical fiber sensor may be configured embedded in the second sensing layer. A earner comprising a first and second sensing layer may facilitate that the first optical fiber sensor and the second optical fiber sensor may be exposed to the same parameters to different degrees. For instance, the optical fiber sensor in the layer configured closest to the (human) skin may be exposed to both a pressure and a temperature of the (human) skin on the earner, while the other optical fiber sensor may be equally exposed to the pressure, but less exposed to the temperature. Further, a earner comprising a first and second sensing layer, each comprising an optical fiber sensor, may facilitate measuring the same or different parameters at the same location with at least two optical fiber sensors, thereby improving one or more of the accuracy of the measurement and the amount of data recorded per location in the earner.

[0048] Hence, the earner may comprise the first sensing layer and the second sensing layer. In embodiments, the first sensing layer and the second sensing layer may be configured in physical contact with each other in the carrier. Alternatively, the first sensing layer and the second sensing layer may be configured separated by one or more further layers in (the layer stack of) the earner. Especially, the earner may comprise a thermally insulating layer. The thermally insulating layer may be configured between the first sensing region and the second sensing region (e.g. as the third (sensing) region). Further, the thermally insulating layer may be configured between the first sensing layer and the second sensing layer (in the layer stack). In embodiments, the thermally insulating layer may be configured in physical contact with the first sensing layer and the second sensing layer. Alternatively, one or more further layers may be configured (i) between the first sensing layer and the thermally insulating layer, and / or (ii) between the second sensing layer and the thermally insulating layer. In embodiments, the thermally insulating layer may comprise a thermally insulating material. The thermally insulating material may especially have a thermal conductivity of < 20 W / (m*K), like < 20 W / (m*K), such as < 10 W / (m*K), especially < 5 W / (m*K), like < 2 W / (m*K). Further, the thermally insulating material may especially have a thermal conductivity of < 1.5 W / (m*K),such as < 1 W / (m*K), especially < 0.5 W / (m*K). The thermally insulating material may comprise one of more of wool, fleece, cork, thermally insulating polymers (e.g. acrylonitrile, polyester, nylon), and down (feathers). Hence, the third region, such as the third earner material, may (further) comprise one or more of wool, fleece, cork, thermally insulating polymers (e.g. acrylonitrile, polyester, nylon), and down (feathers).

[0049] Alternatively, the earner may comprise a thermally conductive layer. The thermally conductive layer may be configured between the first sensing region and the second sensing region (e.g. as the third (sensing) region). Further, the thermally conductive layer may be configured between the first sensing layer and the second sensing layer (in the layer stack). Further, in embodiments, the thermally conductive layer may be configured in physical contact with the first sensing layer and the second sensing layer. Alternatively, one or more further layers may be configured (i) between the first sensing layer and the thermally conductive layer, and / or (ii) between the second sensing layer and the thermally conductive layer. The thermally conductive layer may comprise a thermally conductive material, such as a material having a thermal conductivity of > 20 W / (m*K), like > 30 W / (m*K), such as > 100 W / (m*K), especially > 200 W / (m*K). In embodiments, the thermally conductive material may comprise a thermally conductive polymer or thermally conductive fiber. Additionally or alternatively, the thermally conductive material may comprise one or more of copper, aluminum, aluminum oxide, silver, gold, aluminum nitride, boron nitride, aluminum silicon carbide, beryllium oxide, aluminum silicon carbide, a copper tungsten alloy, a copper molybdenum carbide, carbon, and graphite. Hence, the third region, such as the third earner material, may (further) comprise one or more of copper, aluminum, aluminum oxide, silver, gold, aluminum nitride, boron nitride, aluminum silicon carbide, beryllium oxide, aluminum silicon carbide, a copper tungsten alloy, a copper molybdenum carbide, carbon, and graphite.

[0050] In embodiments, the thermally insulating layer or thermally conductive layer may be configured in contact with the first (and / or second) sensing layer over the full surface area of the first (and / or second) sensing layer. Alternatively, the thermally insulating layer or thermally conductive layer may be configured in between part of the first sensing layer and the second sensing layer. That is, in some part(s) of the earner, the first sensing layer and the second sensing layer may be configured separated by the thermally insulating layer or thermally conductive layer, and in (an)other part(s) of the earner, the first sensing layer may be configured in (direct) physical contact with the second sensing layer. Hence, in specific embodiments, one of the following may apply: (A) the earner may comprise a thermally insulating layer, wherein the thermally insulating layer may be configured between the firstsensing layer and the second sensing layer; and (B) the earner may comprise a thermally conductive layer, wherein the thermally conductive layer may be configured between the first sensing layer and the second sensing layer. A thermally insulating layer may facilitate that the optical fiber sensor configured furthest from the skin (i.e., behind the thermally insulating layer) may be unaffected by a temperature change caused by (human) skin coming in contact with the earner. Hence, said optical fiber sensor may for instance only be affected by a (change in) pressure, while being shielded from temperature effects, thereby simplifying the analysis of the data from this optical fiber sensor, and facilitating using the data from this optical fiber sensor to decouple a pressure signal from the data from another optical fiber sensor. Alternatively, the thermally conductive layer may provide the benefit that the optical fiber sensors in the first sensing layer and the second sensing layer may be similarly affected by (changes in) the temperature, thereby facilitating that the optical fiber sensors may provide comparable signals, which may simplify signal processing.

[0051] As indicated above, one of the first and second sensing regions may be configured closer to a (sur)face of the earner than another of the first and second sensing regions. Further, the first sensing region, such as the first sensing layer, may comprise the first optical fiber sensor (such as the first sensor array). Additionally, the second sensing region, such as the first sensing layer, may comprise the second optical fiber sensor (such as the second sensor array). The first and second sensor arrays may be configured parallel (i.e., a plane of the (2D) first sensor array may be parallel to a plane of the (2D) second sensor array). Yet, the first and second sensor arrays may be configured spatially separated (along at least a direction perpendicular to the plane of the first (and / or second sensor array). Further, the first and second optical fiber sensors may be configured spatially separated. Especially, in a rest state (or “unburdened” state) of the earner, the first and second optical fiber sensor(s) (arrangements, see below), such as the first and second sensor arrays, may be configured (spatially) separated by a shortest distance (zi). In embodiments, zi > 0.05 cm may apply, such as zi > 0.1 cm, especially zi > 0.2 cm. Further, zi > 0.5 cm may apply, such as zi > 1 cm, especially zi > 2 cm, like zi > 3 cm. Additionally or alternatively, zi < 20 cm may apply, such as zi < 15 cm, especially zi < 10 cm, like zi < 5 cm. Would the first and second optical fiber sensors (such as the first and second sensor arrays) be spatially separated, the first and second sensing regions (such as the first and second sensing layers) may be configured in physical contact or spatially separated.

[0052] As indicated above, the light source may be configured to provide light source light to one or more of the n optical fiber sensors. In embodiments, the light source may beconfigured to provide light source light to each of the n optical fiber sensors individually. Alternatively, the n optical fiber sensors may be divided over a plurality of subsets, wherein the light source may be configured to provide light source light to each of the subsets individually. For instance, each subset of optical fiber sensors may be comprised by a single optical fiber, wherein the light source may be configured to provide the light source light to said optical fiber. Alternatively, the light source may be configured to provide the light source light to all of the n optical fiber sensors. Especially, the control system may be configured to control the light source, wherein the control system may especially be configured to determine which (one or more) of the n optical fiber sensors the light source may provide light source light to. In embodiments, the light source may be configured to inject the light source light into an optical fiber comprising at least one of the n optical fiber sensors (wherein the light source may especially be a laser light source). In such embodiments, the light source light may propagate along the optical fiber to reach the optical fiber sensor. Alternatively, the light source may be configured to irradiate at least one of the n optical fiber sensors from an exterior of the optical fiber (sensor). For instance, in such embodiments, the optical fiber sensor may be a fluorescence-based fiber-optic probe.

[0053] The n optical fiber sensors may be functionally coupled to a detector. Further, the detector may be functionally coupled to each of the n optical fiber sensors individually. Alternatively, the n optical fiber sensors may be divided into subsets, wherein each subset of optical fiber sensors may be comprised by the same optical fiber, and wherein the detector may be functionally coupled to (each of) the optical fiber(s) (individually). The detector may be configured to detect an optical signal, i.e., the detector may be a photodetector. Especially, in embodiments, the detector may comprise, such as be, a spectrometer. Additionally or alternatively, the detector may comprise an interferometer. The detector may have a spectral resolution defined by the smallest difference in wavelengths (AX) that can be distinguished at a specific wavelength ( ). In embodiments, the smallest difference in wavelengths (AX) that can be distinguished may be at least partially determined by a full width at half maximum (FWHM) of the (spectral) peak at the specific wavelength (X). In embodiments, the detector may have a spectral resolution of < 2 nm, such as < 1 nm, especially < 0.5 nm, at a wavelength of 500 nm. Additionally or alternatively, the detector may have a spectral resolution of > 0.01 nm, such as > 0.05 nm, especially > 0.1 nm, at a wavelength of 500 nm.

[0054] The detector may be configured to detect an optical response signal (from the n optical fiber sensors). Especially, the light source may be configured to provide light source light to (one or more of) the n optical fiber sensors, and the detector may be configured todetect an optical response signal from said (one or more of the) n optical fiber sensors. As indicated above, the n optical fiber sensors may be configured to affect an intensity and / or spectral power distribution of light provided to the optical fiber sensor, wherein the degree to which the intensity and / or spectral power distribution of the light is affected may be related to (a magnitude or presence of) an external stimulus. Hence, the optical response signal may comprise modulated light source light. In embodiments, one or more of the n optical fiber sensors may be operated in a transmission mode, wherein the light source light may be provided to the optical fiber sensor from a first end of the optical fiber sensor, and wherein the detector may be configured to detect the optical response signal from a second end of the optical fiber sensor, opposite the first end. Additionally or alternatively, one or more of the n optical fiber sensors may be operated in a reflection mode, wherein the light source light may be provided to the optical fiber sensor from a first end of the optical fiber sensor, and wherein the detector may be configured to detect the optical response signal from the first end of the optical fiber sensor. A combination of a transmission mode and a reflection mode may also be possible, wherein the detector may be configured to detect the optical response signal from both ends of the optical fiber sensor (and wherein the light source light may be provided to the optical fiber sensor from the first end).

[0055] The optical response signal may comprise an optical response signal from each of the n optical fiber sensors. Alternatively, (only) part of the optical fiber sensors may receive light from the light source, wherein the optical response signal may comprise the optical response signals from said optical fiber sensors. The optical response signal may be a combined optical response signal from the irradiated optical fiber sensors. Alternatively, the detector may be configured to detect an optical response signal from each (subset) of the irradiated optical fiber sensors separately. Especially, in embodiments, the optical response signal may comprise a first optical response signal from the first optical fiber sensor. Additionally or alternatively, the optical response signal may comprise a second optical response signal from the second optical fiber sensor. That is, the optical response signal may comprise one or more selected from the group of: (i) a first optical response signal from the first optical fiber sensor, and (ii) a second optical response signal from the second optical fiber sensor. The first optical response signal and the second optical response signal may be detected separately or as a combined optical response signal.

[0056] The detector may further be configured to provide the optical response signal to the control system. Hence, the sensing system may comprise a control system. The control system may be configured to control one or more of the light source and the detector. The teim“controlling” and similar terms may (at least) refer to determining the behavior or supervising the running of an element. Hence, herein “controlling” and similar terms may e.g. refer to imposing behavior on the element, such as e.g. measuring, displaying, actuating, opening, shifting, changing temperature, etc.. Beyond that, the term “controlling” and similar terms may include monitoring. Hence, the term “controlling” and similar terms may include imposing behavior on an element and also monitoring the element. The controlling of the element can be done with a control system. The control system and the element may thus at least temporarily, or permanently, be functionally coupled. Control may be done via wired and / or wireless control. Especially, the control system may be configured to receive and execute instructions from a remote control. Further, the control system may be controlled via an App on a device, such as a portable device, like a smartphone, a tablet, etc.. In such embodiments, the control system may be a slave control system or control in a slave mode. The term “control system” may also refer to a plurality of different control systems, which especially are functionally coupled, and of which e.g. one control system may be a master control system and one or more others may be slave control systems. A control system may comprise or may be functionally coupled to a user interface.

[0057] The control system may be configured to receive the optical response signal from the detector. Further, the control system may be configured to determine at least one, such as at least two, especially at least three, parameters based on the optical response signal. Additionally or alternatively, the control system may be configured to determine at most six, such as at most five, especially at most four, parameters based on the optical response signal. Hence, the control system may be configured to determine y parameters based on the optical response signal, wherein 1 < y < 6, such as 2 < y < 5, especially 3 < y < 4. Especially, y may be selected from the range of > 2. In embodiments, the y parameters may be parameter types. Further, the (y) parameter types may be (individually) selected from the group comprising a pressure, a temperature, a (relative) humidity, a strain, and a shear. As indicated above, y may be at least two. That is, the control system may be configured to determine at least two parameters based on the optical response signal. Further, in specific embodiments, the at least two parameters may be parameter types selected from the group comprising a pressure, a temperature, a humidity, a strain, and a shear. Such parameter types may be especially relevant for determining a risk of developing or a presence of e.g. pressure ulcers or other skin conditions. Further, such parameter types may be especially relevant for determining the recovery of a joint (e.g. after an injury or surgery).In embodiments, the y (such as the at least two) parameters may relate to an absolute value of the parameter. That is, the y parameters may relate to a (current) pressure, temperature, (relative) humidity, strain, and stress at the location of the optical fiber sensor providing the optical response signal. Alternatively, the y (such as the at least two) parameters may relate to a change (over time) in the value of the parameter. Especially, the optical response signal may comprise optical response signals from different time points, wherein the control system may be configured to determine a change (over time) in the value of the y parameters based on the optical response signals from different time points. That is, the y (such as the at least two) parameters may relate to a change (over time) in (the value of) (i) the pressure, (ii) the temperature, (iii) the (relative) humidity, (iv) the strain, and (v) the stress (at the location of the optical fiber sensor providing the optical response signal). Hence, in specific embodiments, the at least two parameters may relate to an absolute value of the parameter, or a change in the value of the parameter. Determining an absolute value of a parameter may provide the benefit that a current status of (a human in contact with) the sensing system may be assessed, such that e.g. a fever, overloading, or excessive friction may be detected. Yet, determining a parameter relating to a change (over time) in the value of the parameter may facilitate assessing a development of the parameter over time, such that e.g. the development of a fever, or the development of fluid build-up in the carrier may be detected.

[0058] In embodiments, the y parameters may be of the same parameter type. For instance, the y parameters may (all) be of the parameter type pressure. In such embodiments, especially (y=2 may apply, wherein) a first parameter may relate to an absolute value of the parameter, and a second parameter may relate to a change (over time) in the value of the parameter. Yet, especially, the y parameters, especially the at least two parameters, may differ in parameter type. Hence, the y parameters may be parameter types uniquely selected from the group comprising a pressure, a temperature, a (relative) humidity, a strain, and a shear. Hence, in specific embodiments, (the) at least two (of the) parameters may differ in parameter type.

[0059] As indicated above, the optical response signal may comprise one or more of a first optical response signal from the first optical fiber sensor and a second optical response signal from the second optical fiber sensor. Especially, the optical response signal may comprise (both of) the first optical response signal and the second optical response signal. In such embodiments, the y parameters, such as especially the at least two parameters, may be determined (at least partially, such as fully) from the first optical response signal and the second optical response signal. Hence, in specific embodiments, the at least two parameters may be determined from the first optical response signal and the second optical response signal.Determining the at least two parameters from the (separate) optical response signals of two optical fiber sensors may provide the benefit that the at least two parameters may be determined more accurately than when said parameters would be determined from an optical response signal of a single optical fiber sensor. Further details regarding how the at least two parameters are determined from the optical response signal are provided further below.

[0060] The optical response signal may comprise information regarding the y parameters. That is, the n optical fiber sensors may (each) be sensitive towards one or more of the parameter types. Further, the n optical fiber sensors may (each) have a measurement range over which they may (be able to) measure the one or more of the parameter types. As indicated above, several of the optical fiber sensor types may indicate (a change in) the magnitude of an external stimulus (such as the parameter types) by a change in one or more (peak) wavelengths in the optical response signal, as compared to a (peak) wavelength in the light source light. Hence, the sensitivity of an optical fiber sensor may be indicated by the magnitude of the wavelength shift (compared to the spectrum of the light source light) per unit of the relevant parameter (i.e., the sensitivity may have units nm / U or pm / U, wherein U is the unit of the relevant parameter, e.g. kPa for pressure or °C for temperature).

[0061] In embodiments, at least one of the n optical fiber sensors may be sensitive to pressure (exerted on the optical fiber sensor). Said at least one optical fiber sensor may be configured to detect pressures of > 0 kPa, such as > 1 kPa, especially > 5 kPa, like > 10 kPa. Further, said at least one optical fiber sensor may be configured to detect pressures of > 50 kPa, such as > 100 kPa, especially > 200 kPa, like > 250 kPa. Additionally or alternatively, said at least one optical fiber sensor may be configured to detect pressures of < 1100 kPa, such as < 1000 kPa, especially < 700 kPa, like < 600 kPa. Further, said at least one optical fiber sensor may be configured to detect pressures of < 500 kPa, such as < 400 kPa, especially < 100 kPa, like < 50 kPa, such as < 30 kPa. Hence, said at least one optical fiber sensor may be configured to detect pressures in the range of 0-700 kPa, such as in the range of 0-600 kPa, especially in the range of 50-500 kPa, like in the range of 100-400 kPa. Further, said at least one optical fiber sensor may be configured to detect pressures in the range of 100-1000 kPa, such as in the range of 200-1000 kPa, especially in the range of 200-600 kPa. Yet, said at least one optical fiber sensor may be configured to detect pressures in the range of 0-100 kPa, such as in the range of 0-50 kPa, especially in the range of 0-30 kPa, like in the range of 1-30 kPa. Said at least one optical fiber sensor may further have a sensitivity towards pressure (increases and decreases), i.e., a pressure sensitivity, of > 1 pm / kPa, such as > 3 pm / kPa, especially > 5 pm / kPa, like > 7 pm / kPa. Further, said at least one optical fiber sensor may have a pressuresensitivity of > 15 pm / kPa, such as > 25 pm / kPa, especially > 35 pm / kPa, like > 45 pm / kPa. Additionally or alternatively, said at least one optical fiber sensor may have a pressure sensitivity of < 400 pm / kPa, such as < 300 pm / kPa, especially < 250 pm / kPa, like < 200 pm / kPa. Further, said at least one optical fiber sensor may have a pressure sensitivity of < 100 pm / kPa, such as < 90 pm / kPa, especially < 80 pm / kPa, like < 70 pm / kPa. Hence, said at least one optical fiber sensor may have a pressure sensitivity selected from the range of 1-400 pm / kPa, such as from the range of 5-300 pm / kPa, especially from the range of 5-250 pm / kPa, like from the range of 7-200 pm / kPa. Further, said at least one optical fiber sensor may have a pressure sensitivity selected from the range of 15-100 pm / kPa, such as from the range of 25-90 pm / kPa, especially from the range of 35-80 pm / kPa, like from the range of 45-70 pm / kPa.

[0062] Additionally or alternatively, at least one optical fiber sensor may be sensitive to temperature. Said at least one optical fiber sensor may be configured to detect temperatures of > 10 °C, such as > 15 °C, especially > 20 °C, like > 30 °C, more especially > 31 °C. Additionally or alternatively, said at least one optical fiber sensor may be configured to detect temperatures of < 55 °C, such as < 50 °C, especially < 45 °C, like < 40 °C, more especially < 37 °C. Hence, in embodiments, said at least one optical fiber sensor may be configured to detect temperatures in the range of 10-55 °C, such as in the range of 15-50 °C, especially in the range of 20-45 °C, like in the range of 30-40 °C, more especially in the range of 31-37 °C. Said at least one optical fiber sensor may further have a sensitivity towards temperature (increases and decreases), i.e., a temperature sensitivity, of > 3 pm / °C, such as > 5 pm / °C, especially > 10 pm / °C, like > 20 pm / °C. Further, said at least one optical fiber sensor may have a temperature sensitivity of > 80 pm / °C, such as > 90 pm / °C, especially > 100 pm / °C. Additionally or alternatively, said at least one optical fiber sensor may have a temperature sensitivity of < 280 pm / °C, such as < 260 pm / °C, especially < 240 pm / °C, like < 220 pm / °C. Further, said at least one optical fiber sensor may have a temperature sensitivity of < 180 pm / °C, such as < 160 pm / °C, especially < 140 pm / °C. Hence, said at least one optical fiber sensor may have a temperature sensitivity selected from the range of 3-280 pm / °C, such as from the range of 5-260 pm / °C, especially from the range of 10-240 pm / °C, like from the range of 20-220 pm / °C. Further, said at least one optical fiber sensor may have a temperature sensitivity selected from the range of 80-180 pm / °C, such as from the range of 90-160 pm / °C, especially from the range of 100-140 pm / °C.

[0063] Additionally or alternatively, at least one optical fiber sensor may be sensitive to (relative) humidity. Said at least one optical fiber sensor may be configured to detect a (relative) humidity of > 3%, such as > 5%, especially > 10%. Further, said at least one opticalfiber sensor may be configured to detect (relative) humidities of > 20%, such as > 30%, especially > 40%. Additionally or alternatively, said at least one optical fiber sensor may be configured to detect a (relative) humidity of < 100%, such as < 95%, especially < 90%. Hence, in embodiments, said at least one optical fiber sensor may be configured to detect a (relative) humidity in the range of 3-100%, such as in the range of 5-100%, especially in the range of 10-100%. Further, said at least one optical fiber sensor may be configured to detect a (relative) humidity in the range of 20-100%, such as in the range of 30-100%, especially in the range of 40-95%. Said at least one optical fiber sensor may further have a sensitivity towards (relative) humidity (increases and decreases), i.e., a (relative) humidity sensitivity, of > 3 pm / %, such as > 5 pm / %, especially > 10 pm / %. Additionally or alternatively, said at least one optical fiber sensor may have a (relative) humidity sensitivity of < 300 pm / %, such as < 250 pm / %, especially < 200 pm / %. Hence, said at least one optical fiber sensor may have a (relative) humidity sensitivity selected from the range of 3-300 pm / %, such as from the range of 5-250 pm / %, especially from the range of 10-200 pm / %.

[0064] Additionally or alternatively, at least one optical fiber sensor may be sensitive to strain. Said at least one optical fiber sensor may be configured to detect a strain of > 0.5 ps, such as > 1 ps, especially > 5 ps, like > 10 ps. Additionally or alternatively, said at least one optical fiber sensor may be configured to detect a strain of < 3000 ps, such as < 2000 ps, especially < 1000 ps, like < 800 ps. Hence, in embodiments, said at least one optical fiber sensor may be configured to detect a strain in the range of 0.5-3000 ps, such as in the range of 1-2000 ps, especially in the range of 5-1000 ps, like in the range of 10-800 ps. Said at least one optical fiber sensor may further have a sensitivity towards strain (increases and decreases), i.e., a strain sensitivity, of > 0.5 pm / ps, such as > 1 pm / ps, especially > 2 pm / ps. Additionally or alternatively, said at least one optical fiber sensor may have a strain sensitivity of < 10 pm / ps, such as < 8 pm / ps, especially < 6 pm / ps. Hence, said at least one optical fiber sensor may have a strain sensitivity selected from the range of 0.5-10 pm / ps, such as from the range of 1-8 pm / ps, especially from the range of 2-6 pm / ps.

[0065] Additionally or alternatively, at least one optical fiber sensor may be sensitive to shear. Said at least one optical fiber sensor may be configured to detect a shear of > 0 N, such as > 2 N, especially > 5 N, like > 10 N, such as > 15 N. Additionally or alternatively, said at least one optical fiber sensor may be configured to detect a shear of < 55 N, such as < 50 N, especially < 45 N, like < 40 N, such as < 35 N. Hence, in embodiments, said at least one optical fiber sensor may be configured to detect a shear in the range of 0-55 N, such as in the range of 0-50 N, especially in the range of 5-45 N, like in the range of 10-40 N, such as in the range of15-35 N. Said at least one optical fiber sensor may further have a sensitivity towards shear (increases and decreases), i.e., a shear sensitivity, of > 0.01 pm / N, such as > 0.05 pm / N, especially > 0.1 pm / N. Additionally or alternatively, said at least one optical fiber sensor may have a shear sensitivity of < 2 pm / N, such as < 1.5 pm / N, especially < 1 pm / N. Hence, said at least one optical fiber sensor may have a shear sensitivity selected from the range of 0.01-2 pm / N, such as from the range of 0.05-1.5 pm / N, especially from the range of 0.1-1 pm / N.

[0066] In embodiments, at least two of the n optical fiber sensors may be configured to measure the same parameter type(s). Further, all of the n optical fiber sensors may be configured to measure the same parameter type(s). Alternatively, at least two of the n optical fiber sensors may be configured to measure a(t least one) different parameter type. Further, in embodiments, at least two of the n optical fiber sensors may have the same measurement range and / or sensitivity for one or more of the parameter types. Further, all of the n optical fiber sensors may have the same measurement range and / or sensitivity for one or more of the parameter types. Alternatively, at least two of the n optical fiber sensors may have a different measurement range and / or sensitivity for one or more of the parameter types (e.g. depending on the locations of the respective optical fiber sensors in the earner arrangement). Hence, in embodiments, the first optical fiber sensor and the second optical fiber sensor may have the same sensitivity towards one or more of the parameter types. Alternatively, the first optical fiber sensor and the second optical fiber sensor may have a different sensitivity towards one or more of the parameter types. A difference in sensitivity may be due to a difference in the optical fiber sensor type. Alternatively, the difference in sensitivity may be due to a difference in configuration and / or composition of the first optical fiber sensor and the second optical fiber sensor. Additionally or alternatively, the difference in sensitivity may be due to a difference in location of the first optical fiber sensor and the second optical fiber sensor in the carrier arrangement. Hence, in specific embodiments, the first optical fiber sensor and the second optical fiber sensor may differ in a sensitivity towards one or more of the parameter types. Such a difference in sensitivity may facilitate relatively easily decoupling one or more parameters from a difference in the first optical response signal and the second optical response signal. Further, a difference in sensitivity may facilitate measuring a first parameter (type) with the first optical fiber sensor, and a second parameter (type) with the second optical fiber sensor.

[0067] In embodiments, the control system may be configured to determine the y parameters, such as especially the at least two parameters, based on the optical response signal (comprising one or more of the first optical response signal and the second optical response signal). Further, the control system may be configured to derive information from the yparameters, such as especially from the at least two parameters. Especially, in embodiments, the control system may be configured to derive from the at least two (or y) parameters information about a condition of the earner arrangement. The condition of the earner arrangement may comprise one or more of a pressure on, a temperature of, a humidity in, a strain on, and a shear (force) exerted on the earner arrangement. Further, the control system may be configured to derive from the at least two (or y) parameters information about a change in the condition of the earner arrangement. Hence, the control system may be configured to derive from the at least two (or y) parameters information about one or more of a change in pressure on, a change in temperature of, a change in humidity in, a change in strain on, and change in a shear (force) exerted on the carrier arrangement. Additionally or alternatively, the control system may be configured to derive from the at least two (or y) parameters information about a condition in an environment surrounding the earner arrangement. In embodiments, the environment surrounding the earner arrangement may comprise air. Additionally or alternatively, the environment surrounding the earner arrangement may comprise water or another liquid. Further, the environment surrounding the earner arrangement may comprise one or more of a (bed) frame, clothing, a (plaster or plastic) cast, and a support for the carrier arrangement. The condition in an environment surrounding the earner arrangement may especially comprise one or more of a pressure in, a temperature of, and a humidity in the environment. Further, the condition in an environment surrounding the earner arrangement may comprise one or more of a strain and a shear (force) exerted in the environment. Additionally or alternatively, the control system may be configured to derive from the at least two (or y) parameters information about a change in a condition in an environment surrounding the earner arrangement. Hence, the control system may be configured to derive from the at least two (or y) parameters information about one or more of a change in pressure, a change in temperature, and a change in humidity in the environment. Further, the control system may be configured to derive from the at least two (or y) parameters information about one or more of a change in strain and a change in a shear (force) in the environment.

[0068] Additionally or alternatively, the control system may be configured to derive from the at least two (or y) parameters information about a condition of a human (or animal) in physical contact with the earner. The condition of the human (or animal) in physical contact with the earner may especially comprise one or more of a pressure on, a (local skin) temperature of, a humidity of (the skin of), a strain on (the skin of), and a shear (force) exerted on (the skin of) the human (or animal). Further, the control system may be configured to derive from the at least two (or y) parameters information about a change in a condition of a human(or animal) in physical contact with the carrier. Hence, the control system may be configured to derive from the at least two (or y) parameters information about one or more of a change in pressure on, a change in (local skin) temperature of, a change in humidity of (the skin of), a change in strain on (the skin of), and change in a shear (force) exerted on (the skin of) the human (or animal). Hence, in specific embodiments, the control system may be configured to derive information about a condition of a human in physical contact with the earner, or a change thereof. A control system deriving information about (a change in) a condition of a human in physical contact with the earner may allow monitoring of the position of a patient in a hospital bed, or a recovery of a joint in a patient wearing the sensing system, i.e., such a sensing system may provide information regarding a health state of a person to said person or a caregiver, thereby allowing for an improved recovery time and / or a prevention of (an exacerbation in) a condition.

[0069] The control system may further be configured to generate at least one output signal based on the information (derived from the at least two parameters). In embodiments, the at least one output signal may comprise one or more of a value for the parameter, (a graph displaying) a change (over time) in the value of the parameter, a (heat) map indicating the distribution or variation in the value for the parameter (change) over (at least part of) the sensing system, a risk score, and an action prompt. Hence, the at least one output signal may comprise one or more of a value for (i) the (absolute) pressure, (ii) the (absolute) temperature, (ii) the (absolute) humidity, (iv) the (absolute) strain, and (v) the (absolute) shear, wherein the value may be an average value for (at least part of) the sensing system, or a local value, optionally coupled to the location from which the optical response signal was obtained. Additionally or alternatively, the at least one output signal may comprise (a graph displaying) a change (over time) in one or more of (i) the pressure, (ii) the temperature, (iii) the humidity, (iv) the strain, and (v) the shear, wherein the change may be an average change over (at least part of) the sensing system, or a local change, optionally coupled to the location from which the optical response signal was obtained. Additionally or alternatively, the at least one output signal may comprise a (heat) map indicating a distribution or variation of an absolute value for the parameter or a change in the parameter over the sensing system, i.e., the (heat) map may show, for each optical fiber sensor for which an optical response signal is recorded, the local value for the parameter or change in the parameter at the location of the respective optical fiber sensor, thereby providing a 2D or 3D map of the sensing system in which the value for the parameter (change) may be indicated per optical fiber sensor (or per group of optical fiber sensors). Additionally or alternatively, the at least one output signal may comprise a risk score.For instance, the control system may be configured to determine (or calculate) a risk score for developing a pressure ulcer or a sports injury based on the information, wherein the information may e.g. comprise one or more of a pressure, a temperature, and a humidity of the skin of a human in contact with the carrier, and wherein the control system may be configured to provide the risk score as output (e.g. to be displayed on a user interface). Additionally or alternatively, the at least one output signal may comprise an action prompt. For instance, the control system may be configured to determine a risk score based on the information, wherein the control system may generate an action prompt to notify a caregiver or a person using the sensing system to e.g. turn a patient to prevent tissue damage, adjust a form during exercise to prevent joint pain or injury, or adjust a posture of the user to prevent e.g. back pain.

[0070] As indicated above, the n optical fiber sensors may comprise the first optical fiber sensor and the second optical fiber sensor. Further, the sensing system may comprise a first optical fiber sensor arrangement and a second optical fiber sensor arrangement. The first optical fiber sensor arrangement may comprise a first optical fiber part. The first optical fiber part may especially comprise the first optical fiber sensor. Further, the first optical fiber part may comprise a primary first anchoring point and a secondary first anchoring point. In embodiments, the primary first anchoring point and the secondary first anchoring point may be configured on either side of the first optical fiber sensor (along the first optical fiber part). That is, looking along the first optical fiber part, the first optical fiber sensor may be configured between the primary first anchoring point and the secondary first anchoring point. Further, the primary first anchoring point and the secondary first anchoring point may be configured to constrain a movement of (at least part of) the first optical fiber part configured between the primary first anchoring point and the secondary first anchoring point. Hence, would a strain (e.g. due to tugging) be applied on a part of the optical fiber outside of the first optical fiber part configured between the primary first and secondary first anchoring point, said stain would not be transferred to the first optical fiber part configured between the primary first and secondary first anchoring point, and would therefore not lead to a change in the first optical response signal from the first optical fiber sensor.

[0071] Further, the second optical fiber sensor arrangement may comprise a second optical fiber part. The second optical fiber part may especially comprise the second optical fiber sensor. Further, the second optical fiber part may comprise a primary second anchoring point and a secondary second anchoring point. In embodiments, the primary second anchoring point and the secondary second anchoring point may be configured on either side of the second optical fiber sensor (along the second optical fiber part). That is, looking along the secondoptical fiber part, the second optical fiber sensor may be configured between the primary second anchoring point and the secondary second anchoring point. Further, the primary second anchoring point and the secondary second anchoring point may be configured to constrain a movement of (at least part of) the second optical fiber part configured between the primary second anchoring point and the secondary second anchoring point. Hence, would a strain (e.g. due to tugging) be applied on a part of the optical fiber outside of the second optical fiber part configured between the primary second and secondary second anchoring point, said strain would not be transferred to the second optical fiber part configured between the primary second and secondary second anchoring point, and would therefore not lead to a change in the second optical response signal from the second optical fiber sensor. Hence, in specific embodiments, the sensing system may comprise a first optical fiber sensor arrangement and a second optical fiber sensor arrangement; wherein: (A) the first optical fiber sensor arrangement may comprise a first optical fiber part, wherein the first optical fiber part may comprise the first optical fiber sensor, a primary first anchoring point, and a secondary first anchoring point; wherein the primary first anchoring point and the secondary first anchoring point may be configured on either side of the first optical fiber sensor; and wherein the primary first anchoring point and the secondary first anchoring point may be configured to constrain a movement of the first optical fiber part configured between the primary first anchoring point and the secondary first anchoring point; and (B) the second optical fiber sensor arrangement may comprise a second optical fiber part, wherein the second optical fiber part may comprise the second optical fiber sensor, a primary second anchoring point, and a secondary second anchoring point; wherein the primary second anchoring point and the secondary second anchoring point may be configured on either side of the second optical fiber sensor; and wherein the primary second anchoring point and the secondary second anchoring point may be configured to constrain a movement of the second optical fiber part configured between the primary second anchoring point and the secondary second anchoring point. Such a first (and / or second) optical fiber sensor arrangement may provide the benefit that only forces acting on the first (and / or second) optical fiber part configured between the primary first (and / or second) anchoring point and the secondary first (and / or second) anchoring point may provide a change in the first (and / or second) optical response signal generated by the first (and / or second) optical fiber sensor. Hence, such a first (and / or second) optical fiber sensor arrangement may especially facilitate the measuring of (changes in) local conditions.

[0072] Hence, the sensing system may comprise the first optical fiber sensor arrangement and the second optical fiber sensor arrangement. Alternatively, the first opticalfiber sensor arrangement may be provided separately from the sensing system. That is, in a further aspect, the invention may provide a first optical fiber sensor arrangement, wherein the first optical fiber sensor arrangement may comprises a first optical fiber part, wherein the first optical fiber part may comprise a first optical fiber sensor as defined herein, a primary first anchoring point, and a secondary first anchoring point; wherein the primary first anchoring point and the secondary first anchoring point may be configured on either side of the first optical fiber sensor (along the first optical fiber part); and wherein the primary first anchoring point and the secondary first anchoring point may be configured to constrain a movement of the first optical fiber part configured between the primary first anchoring point and the secondary first anchoring point. Such a first optical fiber sensor arrangement may provide the benefit that only forces acting on the first optical fiber part configured between the primary first and secondary first anchoring point may provide a change in a first optical response signal generated by the first optical fiber sensor. Hence, such a first optical fiber sensor arrangement may especially facilitate measuring (changes in) local conditions. Herein, embodiments relating to one or more of the first optical fiber sensor arrangement, the first optical fiber part, the first optical fiber sensor, the primary first anchoring point, and the secondary first anchoring point of the sensing system of the invention may apply mutatis mutandis to the first optical fiber sensor arrangement, the first optical fiber part, the first optical fiber sensor, the primary first anchoring point, and the secondary first anchoring point of the first optical fiber sensor arrangement of the invention (and vice versa).

[0073] In embodiments, the first optical fiber sensor arrangement and second optical fiber sensor arrangement of the sensing system may comprise part of the same optical fiber. That is, in embodiments, the sensing system may comprise a first optical fiber, wherein the first optical fiber may comprise the first optical fiber part and the second optical fiber part. Alternatively, the first optical fiber sensor arrangement and second optical fiber sensor arrangement may each comprise a part of a different optical fiber. That is, the sensing system may comprise a first optical fiber and a (separate) second optical fiber. In such embodiments, the first optical fiber may comprise the first optical fiber part. Additionally or alternatively, in such embodiments, the second optical fiber may comprise the second optical fiber part. Hence, in specific embodiments, one of the following may apply: (A) the sensing system may comprise a first optical fiber, wherein the first optical fiber may comprise the first optical fiber part and the second optical fiber part; and (B) the sensing system may comprise a first optical fiber and a second optical fiber; wherein the first optical fiber may comprise the first optical fiber part; and wherein the second optical fiber may comprise the second optical fiber part. A sensingsystem wherein the first optical fiber part and the second optical fiber part may be comprised by the same (first) optical fiber may provide the benefit that light source light need only be provided to one optical fiber, thereby providing a more energy-efficient sensing system. Alternatively, a sensing system wherein the first optical fiber part and the second optical fiber part may be comprised by different optical fibers may facilitate providing light with different properties (e.g. different wavelengths, pulse widths, intensities, etc.) to each optical fiber (sensor), thereby providing a more versatile sensing system.

[0074] The first optical fiber sensor, such as the first optical fiber sensor arrangement, may be configured embedded in the first sensing region (e.g. the first sensing layer). Similarly, the second optical fiber sensor, such as the second optical fiber sensor arrangement, may be configured embedded in the second sensing region (e.g. the second sensing layer). Would the first and second optical fiber parts be comprised by the (same) first optical fiber, the first optical fiber may (thus) extend from the first sensing region to the second sensing region. Would the first and second optical fiber parts be comprised by the first and second optical fibers, respectively, the first optical fiber may intersect the first sensing region (and may or may not intersect the second sensing region), and the second optical fiber may intersect the second sensing region (and may or may not intersect the first sensing region).

[0075] Hence, the first optical fiber may comprise (both) the first optical fiber part and the second optical fiber part. In such embodiments, the primary first anchoring point, the secondary first anchoring point, the primary second anchoring point, and the secondary second anchoring point may be sequentially arranged (in that order) along the first optical fiber. The first optical fiber part and the second optical fiber part may be configured separated along the first optical fiber. Especially, the first optical fiber may have a first fiber length Li between the secondary first anchoring point and the primary second anchoring point. In embodiments, Li > 1 cm may apply, such as Li > 2 cm, especially Li > 3 cm. Additionally or alternatively, Li < 20 cm may apply, such as Li < 15 cm, especially Li < 10 cm. Further, the secondary first anchoring point and the primary second anchoring point may be spatially separated (in the earner arrangement) by a first distance di. That is, the secondary first anchoring point may be configured (spatially) separated from the primary second anchoring point by a shortest distance di. In embodiments, di > 0.5 cm may apply, such as di > 1 cm, especially di > 2 cm. Additionally or alternatively, di < 15 cm may apply, such as di < 10 cm, especially di < 5 cm, like di < 4 cm. Further, in embodiments, di > 0.1 *Li may apply, such as di > 0.2*Li, especially di > 0.3 *Li. Additionally or alternatively, in embodiments, di < Li may apply, such as di < 0.9*Li, especially di < 0.8*Li. Hence, in specific embodiments, the first optical fiber maycomprise the first optical fiber part and the second optical fiber part; wherein the primary first anchoring point, the secondary first anchoring point, the primary second anchoring point, and the secondary second anchoring point may be sequentially arranged along the first optical fiber; wherein the first optical fiber may have a first fiber length Li between the secondary first anchoring point and the primary second anchoring point; wherein the secondary first anchoring point and the primary second anchoring point may be spatially separated by a first distance di; and wherein di < 0.9*Li. Such a first fiber length Li and first distance di may facilitate that the first optical fiber between the secondary first anchoring point and the primary second anchoring point may have a longer length than needed to span the first distance di (i.e., the first optical fiber may be configured slack), thereby providing the benefit that stretching of the earner arrangement may not result in a strain on the first optical fiber. Therefore, such a configuration may extend the lifetime of, and prevent damage to, the first optical fiber.

[0076] The first optical fiber sensor arrangement may (further) comprise a first closedshaped fixating element. The first closed-shaped fixating element may be configured encircling the first optical fiber sensor. That is, (looking from a direction perpendicular to the first closedshaped fixating element and the first optical fiber sensor,) the first optical fiber sensor may be configured within the first closed-shaped fixating element. Further, the first optical fiber sensor may be configured in a plane of the first closed-shaped fixating element. Especially, the first closed-shaped fixating element may be configured to encircle the first optical fiber sensor in a first plane, wherein the first optical fiber sensor may not extend beyond the first closed-shaped fixating element in a second plane perpendicular to the first plane. Alternatively, the first optical fiber sensor may be configured to extend beyond the first closed-shaped fixating element in the second plane. Further, in embodiments, the first optical fiber part may be configured fixated to the first closed-shaped fixating element at the primary first anchoring point and the secondary first anchoring point. Especially, the first optical fiber part may be configured fixated to the first closed-shaped fixating element via one or more of gluing (e.g. with an epoxy, polyvinyl, or silicone glue), clamping, screwing, sewing, chemical bonding, melting together (including welding), and soldering at the primary first anchoring point and secondary first anchoring point. In embodiments, the primary first anchoring point and the secondary first anchoring point may be configured on the same half of the first closed-shaped fixating element. Alternatively, and especially, the primary first anchoring point and the secondary first anchoring point may be configured on opposite sides of the first closed-shaped fixating element (in the first plane).As indicated above, the first optical fiber sensor arrangement may be provided as part of the sensing system, yet may further be provided separately from the sensing system. Hence, in specific embodiments, the invention may provide the first optical fiber sensor arrangement, wherein the first optical fiber sensor arrangement may comprise a first closedshaped fixating element, wherein the first closed-shaped fixating element may be configured encircling the first optical fiber sensor; wherein the first optical fiber part may be configured fixated to the first closed-shaped fixating element at the primary first anchoring point the secondary first anchoring point. Such a first closed-shaped fixating element may facilitate that the first optical fiber sensor may (essentially) not be affected by forces (acting on areas) outside of the first closed-shaped fixating element, thereby facilitating the measuring of forces in a small, localized area, such that the spatial resolution of the first optical fiber sensor may be improved. Herein, embodiments relating to the first closed-shaped fixating element of the sensing system of the invention may apply mutatis mutandis to the first closed-shaped fixating element of the first optical fiber sensor arrangement of the invention (and vice versa).

[0077] Further, the second optical fiber sensor arrangement may comprise a second closed-shaped fixating element. The second closed-shaped fixating element may be configured encircling the second optical fiber sensor. That is, (looking from a direction perpendicular to the second closed-shaped fixating element and the second optical fiber sensor,) the second optical fiber sensor may be configured within the second closed-shaped fixating element. Further, the second optical fiber sensor may be configured in a plane of the second closedshaped fixating element. Especially, the second closed-shaped fixating element may be configured to encircle the second optical fiber sensor in a first plane, wherein the second optical fiber sensor may not extend beyond the second closed-shaped fixating element in a second plane perpendicular to the first plane. Alternatively, the second optical fiber sensor may extend beyond the second closed-shaped fixating element in the second plane. Further, in embodiments, the second optical fiber part may be configured fixated to the second closedshaped fixating element at the primary second anchoring point and the secondary second anchoring point. Especially, the second optical fiber part may be configured fixated to the second closed-shaped fixating element via one or more of gluing (e.g. with an epoxy, polyvinyl, or silicone glue), clamping, screwing, sewing, chemical bonding, melting together (including welding), and soldering at the primary second anchoring point and secondary second anchoring point. In embodiments, the primary second anchoring point and the secondary second anchoring point may be configured on the same half of the second closed-shaped fixating element. Alternatively, and especially, the primary second anchoring point and the secondarysecond anchoring point may be configured on opposite sides of the second closed-shaped fixating element (in the first plane). Hence, in specific embodiments, one or more may apply of: (A) the first optical fiber sensor arrangement may comprise a first closed-shaped fixating element, wherein the first closed-shaped fixating element may be configured encircling the first optical fiber sensor; wherein the first optical fiber part may be configured fixated to the first closed-shaped fixating element at the primary first anchoring point and the secondary first anchoring point; and (B) the second optical fiber sensor arrangement may comprise a second closed-shaped fixating element, wherein the second closed-shaped fixating element may be configured encircling the second optical fiber sensor; wherein the second optical fiber part may be configured fixated to the second closed-shaped fixating element at the primary second anchoring point and the secondary second anchoring point. Hence, one or more of the first optical fiber sensor arrangement and the second optical fiber sensor arrangement may have a fixating-element configuration. A first (and / or second) closed-shaped fixating element may facilitate that the first (and / or second) optical fiber sensor may (essentially) not be affected by forces (acting on areas) outside of the first (and / or second) closed-shaped fixating element, thereby facilitating the measuring of forces in a small, localized area, thus improving the spatial resolution of the first (and / or second) optical fiber sensor.

[0078] In embodiments, the first (and / or second) closed-shaped fixating element may comprise a fixating element material. Especially, the fixating element material may be selected from the group comprising metals, (natural and / or synthetic) textiles, (natural and / or synthetic) foam materials, (hardened) glue, wood, ceramics, stone, glass, and plastics. The first (and / or second) closed-shaped fixating element may be configured comprised by the earner. In such embodiments, the first (and / or second) closed-shaped fixating element may be provided by (a) placing the first (and / or second) optical fiber sensor on the material of the earner, (b) encircling the first (and / or second) optical fiber sensor with a glue, wherein the glue passes over the anchoring points of the first (and / or second) optical fiber sensor, thereby fixating the anchoring points, and (c) hardening the glue to provide the first (and / or second) closed-shaped fixating element. Alternatively, the earner may comprise a (natural and / or synthetic) foam material, wherein the foam material has a (pre-determined) variation in flexibility or stiffness, and wherein the first (and / or second) closed-shaped fixating element may be provided by a closedshaped section of high-stiffness foam in the foam material (wherein the anchoring points of the first (and / or second) optical fiber sensor may be clamped in the high-stiffness closed-shaped section of the foam material). Yet, in embodiments, the first (and / or second) closed-shapedfixating element may be a stand-alone element, and may be placed on or (embedded) in the carrier arrangement of the sensing system.

[0079] Further, the first closed-shaped fixating element and second closed-shaped fixating element may have a fixating element shape (in the first plane). In embodiments, the fixating element shape may (for the first and second closed-shaped fixating element individually) be selected from the group comprising a circle, an ellipse, and a simple (regular) polygon, wherein the simple (regular) polygon may have 2-24 sides, and wherein the sides of the simple (regular) polygon may be straight or curved. The fixating element shape may especially be a border shape (or “hollow shape”). That is, would the fixating element shape be a circle, the fixating element shape would resemble an annulus. Especially, the fixating element shape may be a curve-like shape, such as in embodiments a circle. Hence, the first closedshaped fixating element may have a closed curve-like shape. Additionally or alternatively, the second closed-shaped fixating element may have a closed curve-like shape. Hence, in specific embodiments, one or more of the following may apply: (i) the first closed-shaped fixating element may have a closed curve-like shape, and (ii) the second closed-shaped fixating element may have a closed curve-like shape. Such a shape may have relatively little to no edges, reducing the possibility of (accidentally) poking (the skin of) a human (or animal) configured in contact with the sensing system. Further, a closed curve-like shape may better distribute forces, exerted on one point of the closed-shaped fixating element, over the whole of the closed-shaped fixating element, thereby improving the durability of the first (and / or second) closed-shaped fixating element.

[0080] In embodiments, the first optical fiber sensor arrangement (of the invention and / or of the sensing system) may comprise a first diaphragm. Additionally or alternatively, the second optical fiber sensor arrangement may comprise a second diaphragm. The first diaphragm and / or second diaphragm may comprise one or more of a (natural and / or synthetic) textile material and a (polymeric) film. Especially, the first diaphragm and / or second diaphragm may comprise a low-friction material, such as nylon, polyester, a polyimide, polytetrafluoroethylene (PTFE), etc.. The first diaphragm and / or second diaphragm may comprise a damp-proof material. Further, the first diaphragm may be configured fixated to the first closed-shaped fixating element (around a circumference of the first closed-shaped fixating element). In embodiments, the first diaphragm may be configured on one side of the first closed-shaped fixating element. Alternatively, the first diaphragm may be configured on both sides of the first closed-shaped fixating element. In such embodiments, the first diaphragm may be configured covering the first optical fiber sensor from both sides of the first closed-shapedfixating element (i.e., the first diaphragm and first closed-shaped fixating element may be configured to encapsulate or fully enclose the first optical fiber sensor). Further, the second diaphragm may be configured fixated to the second closed-shaped fixating element (around a circumference of the second closed-shaped fixating element). In embodiments, the second diaphragm may be configured on one side of the second closed-shaped fixating element. Alternatively, the second diaphragm may be configured on both sides of the second closedshaped fixating element. In such embodiments, the second diaphragm may be configured covering the second optical fiber sensor from both sides of the second closed-shaped fixating element (i.e., the second diaphragm and second closed-shaped fixating element may be configured to encapsulate or fully enclose the second optical fiber sensor). Hence, in specific embodiments, (A) the first optical fiber sensor arrangement may further comprise a first diaphragm, wherein the first diaphragm may be configured fixated to the first closed-shaped fixating element, and wherein the first diaphragm may be configured covering the first optical fiber sensor; and (B) the second optical fiber sensor arrangement may further comprise a second diaphragm, wherein the second diaphragm may be configured fixated to the second closed-shaped fixating element, and wherein the second diaphragm may be configured covering the second optical fiber sensor. Such a first and second diaphragm may provide protection against ingress for the first and second optical fiber sensor (respectively). Further, such a first and second diaphragm may prevent a material of the earner arrangement and / or a human (or animal) in contact with the earner arrangement from snagging on the first and second optical fiber sensor (respectively).

[0081] In alternative embodiments, the primary first anchoring point and the secondary first anchoring point may be configured mechanically coupled (to each other). In embodiments, the primary first anchoring point and secondary first anchoring point may be configured mechanically coupled via one or more of gluing (e.g. with an epoxy, polyvinyl, or silicone glue), clamping, screwing, sewing, chemical bonding, melting together (including welding), and soldering. Especially, the mechanically coupled primary first anchoring point and secondary first anchoring point may form a first loop. The first loop may especially comprise the first optical fiber sensor. Hence, in specific embodiments, the invention may provide the first optical fiber sensor arrangement, wherein the primary first anchoring point and the secondary first anchoring point may be configured mechanically coupled, thereby forming a first loop. Such a first loop may be relatively easy to produce, yet may prevent forces on the optical fiber outside of the primary and secondary first anchoring point from affecting the first optical response signal of the first optical fiber sensor.Additionally or alternatively, the primary second anchoring point and the secondary second anchoring point may be configured mechanically coupled (to each other). In embodiments, the primary second anchoring point and secondary second anchoring point may be configured mechanically coupled via one or more of gluing (e.g. with an epoxy, polyvinyl, or silicone glue), clamping, screwing, sewing, chemical bonding, melting together (including welding), and soldering. Especially, the mechanically coupled primary second anchoring point and secondary second anchoring point may form a second loop. The second loop may especially comprise the second optical fiber sensor. Hence, in specific embodiments, one or more may apply of: (A) the primary first anchoring point and the secondary first anchoring point may be configured mechanically coupled, thereby forming a first loop; and (B) the primary second anchoring point and the secondary second anchoring point may be configured mechanically coupled, thereby forming a second loop. Hence, one or more of the first optical fiber sensor arrangement and the second optical fiber sensor arrangement may have a loop configuration. A first (and / or second) loop may be relatively easy to produce, yet may prevent forces on the optical fiber outside of the primary and secondary first (and / or second) anchoring point from affecting the first (and / or second) optical response signal of the first (and / or second) optical fiber sensor.

[0082] As indicated above, the first loop may comprise the first optical fiber sensor. Especially, the first optical fiber sensor may be configured (approximately) halfway between the primary first anchoring point and the secondary first anchoring point. That is, the first optical fiber sensor may be configured equidistant (along the first optical fiber part) from the primary first anchoring point and the secondary first anchoring point. Additionally or alternatively, the second optical fiber sensor may be configured (approximately) halfway between the primary second anchoring point and the secondary second anchoring point. Hence, in specific embodiments, the first optical fiber sensor may be configured halfway between the primary first anchoring point and the secondary first anchoring point in the first loop; and the second optical fiber sensor may be configured halfway between the primary second anchoring point and the secondary second anchoring point in the second loop. Configuring the optical fiber sensor (approximately) halfway between the primary anchoring point and the secondary anchoring point may facilitate that, even if some forces from outside the loop would be transferred to the loop, the effect on the optical fiber sensor may be minimized.

[0083] In alternative embodiments, the first optical fiber sensor arrangement may comprise a first encapsulant. The first encapsulant may be configured enclosing the first optical fiber sensor (around a circumference of the first optical fiber sensor). Especially, the firstoptical fiber sensor may have a first longitudinal axis along the (first) optical fiber, wherein the first encapsulant may be configured enclosing the first optical fiber sensor over an angle of > 300°, such as > 330°, especially (essentially) 360°, about the first longitudinal axis. Further, the first optical fiber part may be configured extending from the first encapsulant (on either side of the first encapsulant). The first encapsulant may be configured fixated to at least part of the first optical fiber part. Especially, the first encapsulant may be configured fixated to the first optical fiber part at (at least) the primary first anchoring point and the secondary first anchoring point. Hence, in specific embodiments, the invention may provide the first optical fiber sensor arrangement, wherein the first optical fiber sensor arrangement may comprise a first encapsulant, wherein the first encapsulant may be configured enclosing the first optical fiber sensor; wherein the first optical fiber part may be configured extending from the first encapsulant; and wherein the first encapsulant may be configured fixated to at least part of the first optical fiber part. Such a first encapsulant may facilitate shielding the first optical fiber sensor from the effects of one or more of temperature, humidity, and shear. Hence, such a first optical fiber sensor arrangement may provide a first optical response signal which may relatively strongly correlate to a pressure exerted on or strain experienced by the first optical fiber sensor. Alternatively, such a first encapsulant may shield the first optical fiber sensor from the effects of pressure, wherein the first optical response signal may relatively strongly correlate to a temperature around the first encapsulant. Herein, embodiments relating to the first encapsulant of the sensing system of the invention may apply mutatis mutandis to the first encapsulant of the first optical fiber sensor arrangement of the invention (and vice versa).

[0084] Additionally or alternatively, the second optical fiber sensor arrangement may comprise a second encapsulant. The second encapsulant may be configured enclosing the second optical fiber sensor (around a circumference of the second optical fiber sensor). Especially, the second optical fiber sensor may have a second longitudinal axis along the (first or second) optical fiber, wherein the second encapsulant may be configured enclosing the second optical fiber sensor over an angle of > 300°, such as > 330°, especially (essentially) 360°, about the second longitudinal axis. Further, the second optical fiber part may be configured extending from the second encapsulant (on either side of the second encapsulant). Additionally, the second encapsulant may be configured fixated to at least part of the second optical fiber part. Especially, the second encapsulant may be configured fixated to the second optical fiber part at (at least) the primary second anchoring point and the secondary second anchoring point. Hence, in specific embodiments, one or more may apply of: (A) the first optical fiber sensor arrangement may comprise a first encapsulant, wherein the firstencapsulant may be configured enclosing the first optical fiber sensor; wherein the first optical fiber part may be configured extending from the first encapsulant; and wherein the first encapsulant may be configured fixated to at least part of the first optical fiber part; and (B) the second optical fiber sensor arrangement may comprise a second encapsulant, wherein the second encapsulant may be configured enclosing the second optical fiber sensor; wherein the second optical fiber part may be configured extending from the second encapsulant; and wherein the second encapsulant may be configured fixated to at least part of the second optical fiber part. Hence, one or more of the first optical fiber sensor arrangement and the second optical fiber sensor arrangement may have an encapsulant configuration. A first (and / or second) encapsulant may facilitate shielding the first (and / or second) optical fiber sensor from the effects of one or more of temperature, humidity, and shear. Hence, such a first (and / or second) optical fiber sensor arrangement may provide a first (and / or second) optical response signal which may relatively strongly correlate to a pressure exerted on or strain experienced by the first (and / or second) optical fiber sensor. Alternatively, such a first (and / or second) encapsulant may shield the first (and / or second) optical fiber sensor from the effects of pressure, wherein the first (and / or second) optical response signal may relatively strongly correlate to a temperature around the first (and / or second) encapsulant.

[0085] Hence, the first optical fiber sensor arrangement may comprise a first encapsulant, and the second optical fiber sensor arrangement may comprise a second encapsulant. Hereafter, some general embodiments relating the one or more of the first encapsulant and the second encapsulant may be provided. The encapsulant may be a thermally conductive encapsulant (e.g., the encapsulant may comprise copper). In such embodiments, the optical fiber sensor arrangement in the encapsulant configuration may especially be affected by (changes in) temperature. Alternatively, the encapsulant may be thermally insulating. In such embodiments, the optical fiber sensor arrangement in the encapsulant configuration may be shielded from the effects of (changes in) temperature, and / or the effects of a temperature change on the optical response signal may be delayed. Additionally or alternatively, the encapsulant may be damp-proof, such that the optical fiber sensor arrangement in the encapsulant configuration may be shielded from the effects of (changes in) the humidity. The encapsulant may be a hollow encapsulant. That is, the encapsulant may be configured fixated to the optical fiber part at the primary anchoring point and the secondary anchoring point, wherein the optical fiber part between the primary and secondary anchoring points may move freely within the encapsulant. In such embodiments, the encapsulant may especially be configured fixated to the optical fiber part through one or more of gluing (e.g. with an epoxy,polyvinyl, or silicone glue), clamping, screwing, sewing, chemical bonding, melting together (including welding), and soldering. Alternatively, the encapsulant may be a filled encapsulant (i.e., the encapsulant may be configured in physical contact with the optical fiber part over a full length of the encapsulant). In such embodiments, the encapsulant may have an encapsulant core and an encapsulant shell configured enclosing the encapsulant core, and one of the following may apply: (i) the encapsulant core and encapsulant shell comprise the same material, and (ii) the encapsulant core and encapsulant shell comprise different materials. For instance, the encapsulant shell and encapsulant core may comprise a foam material, wherein the foam may have a higher density and / or stiffness in the encapsulant shell. Alternatively, for instance, the encapsulant shell may comprise a rigid material, and the encapsulant core may comprise a flexible material. Yet, in embodiments, (both) the encapsulant core and the encapsulant shell may comprise a flexible material. Further, would the encapsulant be hollow, the encapsulant may (essentially) consist of the encapsulant shell (and optionally one or more of clamps, glue plugs, and soldering material to fixate the encapsulant to the optical fiber part).

[0086] In embodiments, the encapsulant core may comprise one or more materials selected from the group comprising metals, (natural and / or synthetic) foam, (hardened) glue (e.g. an epoxy, polyvinyl, or silicone glue), down (feathers), cotton, wood, (rigid or flexible) plastic (fibers), silicones, and (natural or synthetic) rubber. Further, the encapsulant shell may comprise one or more materials selected from the group comprising metals (including alloys), glass, wood, ceramics, stone, (synthetic or natural) foam materials, silicones, and plastics. Especially, the encapsulant shell (of the hollow encapsulant or filled encapsulant) may comprise a metal, such as one or more of (stainless and / or galvanized) steel, copper, aluminum, and titanium. In specific embodiments, the encapsulant shell may comprise, such as consist of, stainless steel. Further, the metal encapsulant may especially have a cylindrical shape. Hence, in specific embodiments, one or more of the first encapsulant and the second encapsulant may comprise, such as consist of, a hollow metallic cylinder. Yet, as indicated above, the encapsulant core and shell may comprise the same material. Hence, in embodiments, the encapsulant may be a monolithic encapsulant.

[0087] The (hollow, monolithic, or core-shell) encapsulant may have a shape. Especially, the encapsulant may have (i) a first shape in a cross-section of the encapsulant perpendicular to the optical fiber, such as to the optical fiber sensor, and (ii) a second shape in a cross-section of the encapsulant parallel to the optical fiber, such as to the optical fiber sensor. Each of the first shape and the second shape may be individually selected from the group comprising a circle, an ellipse (or oval), a lens (or “(double-)pointed oval”), a circular sector(e.g. a semi-circle), an elliptic sector (e.g. a semi-ellipse), and a simple regular polygon (e.g. a square or rectangle), wherein the sides of the polygon may be straight or curved, and wherein the comers of the polygon may be sharp or rounded. Further, the encapsulant may have a three-dimensional encapsulant shape, wherein the encapsulant shape may be selected from the group comprising a sphere, an ellipsoid (or ovoid), a semi-ellipsoid (or hemi-ellipsoid, wherein the ellipsoid may especially be halved lengthwise), a cylinder, a disk, a cube, a (rectangular) cuboid, a pillow shape (having a lens as the first shape and a rectangle as the second shape), and a truncated ellipsoid (having a square with (i) two opposite rounded sides or (ii) three rounded sides as the first shape and an ellipse as the second shape). The term “truncated ellipsoid” may refer to an ellipsoid wherein, lengthwise, the ellipsoid may be intersected by (i) a plane configured parallel to but offset with respect to a central axis of the ellipsoid, wherein the shape comprising the central axis may be a (single-)truncated ellipsoid, or (ii) two parallel planes configured parallel to and on opposite sides of the central axis of the ellipsoid, wherein the shape between the two parallel planes may be a (double-)truncated ellipsoid. Especially, the truncated ellipsoid may be a double-truncated ellipsoid. Hence, the encapsulant shape may be selected from the group comprising an ellipsoid, a semi-ellipsoid, a cylinder, a cube, a (rectangular) cuboid, a pillow shape, and a truncated ellipsoid. In specific embodiments, the encapsulant shape may be an ellipsoid, a semi-ellipsoid, or a truncated ellipsoid.

[0088] Herein, phrases like “the encapsulant shape may be selected from an ellipsoid”, and similar phrases, may indicated that the shape of the encapsulant may approximate the shape of an ellipsoid (i.e., may approximate an ellipsoid shape). That is, the encapsulant shape may be nearly identical to, especially identical to, the indicated shape, but may also show a slight deviation from the indicated shape. For example, an encapsulant may have a cuboid shape but for a defect. In particular, a shape approximating a first shape may herein refer to: a first shape realization encompassing the object, wherein the first shape realization has the first shape and is defined as the smallest encompassing shape of the object, wherein a ratio of the volume of the first shape realization to the volume of the object is < 1.2, especially < 1.1, such as < 1.05, especially < 1.02. For instance, the encapsulant may approximate a cuboid shape, wherein the first shape realization may be defined as the smallest cuboid shape encompassing the encapsulant, wherein a ratio of the volume of the first shape realization to the volume of the encapsulant is < 1.2, especially, especially < 1.1, such as < 1.05, especially < 1.02, including 1. Further, the term approximate may refer to the object and the first shape being superimposable, such that an intersection between the object and the first shape covers at leastn% of the object and at least n% of the shape, wherein n is > 90%, such as > 95%, especially > 98%, including 100%.

[0089] The encapsulant may have a largest encapsulant length (LE) along the (first or second) optical fiber (part). Especially, LE > 3 mm may apply, such as LE > 5 mm, especially LE > 7 mm. Additionally or alternatively, LE < 25 mm may apply, such as LE < 15 mm, especially LE < 10 mm. Further, the encapsulant may have a largest equivalent circular diameter (DE) perpendicular to the (first or second) optical fiber (part). Especially, DE > 1 mm may apply, such as DE > 2 mm, especially DE > 3 mm. Additionally or alternatively, DE < 15 mm may apply, such as DE < 10 mm, especially DE < 5 mm. Herein, the equivalent circular diameter (or ECD) of any two-dimensional shape may be the diameter of a circle of equivalent area. For instance, the ECD of a square with side a is 2a / SQRT(7t). For a circle, the diameter is equal to the ECD. Would a circle with diameter D be distorted to any other shape, without changing the area size, then the ECD of that shape would be D.

[0090] The encapsulant may further have an encapsulant volume (VE). The encapsulant volume (VE) may comprise the volume of the encapsulant and a volume of the optical fiber sensor and optical fiber part embedded in the encapsulant. That is, the encapsulant volume (VE) may refer to the volume enclosed by (a surface of) the encapsulant. Especially, VE > 5 mm3may apply, such as VE > 10 mm3, especially VE > 15 mm3. Additionally or alternatively, VE < 2100 mm3may apply, such as VE < 1500 mm3, especially VE < 1000 mm3. Further, VE < 150 mm3may apply, such as VE < 100 mm3, especially VE < 70 mm3, like VE < 50 mm3. Hence, the encapsulant may have an encapsulant volume (VE) selected from the range of 5-150 mm3, such as from the range of 10-100 mm3, especially from the range of 10-70 mm3, like from the range of 15-50 mm3.

[0091] The encapsulant may have a glass transition temperature (Tg). In embodiments, Tg > 45 °C may apply, such as Tg> 50 °C, especially Tg> 55 °C. Further, Tg> 60 °C may apply, such as Tg> 70 °C, especially Tg> 80 °C, like Tg> 90 °C. Additionally or alternatively, in embodiments, Tg< 300 °C may apply, such as Tg< 250 °C, especially Tg< 200 °C. The encapsulant may further have a coefficient of thermal expansion (CTE) (in the temperature range of 25-40 °C). In embodiments, CTE > 40*1 O’6m / (m°C) may apply, such as CTE > 50*1 O’6m / (m°C), especially CTE > 60*1 O’6m / (m°C), like CTE > 70*1 O’6m / (m°C) (and e.g. CTE < 200*1 O’6m / (m°C)). In such embodiments, the optical fiber sensor (embedded in the encapsulant) may especially be sensitive to temperature. Yet, in other embodiments, CTE < 40*1 O’6m / (m°C) may apply, such as CTE < 30*1 O’6m / (m°C), especially CTE < 20*1 O’6m / (m°C), like CTE < 10*1 O’6m / (m°C). In such embodiments, the optical fiber sensor(embedded in the encapsulant) may be relatively insensitive to temperature. Further, the encapsulant may have a Young’s modulus (E). In embodiments, E > 2 GPa may apply, such as E > 3 GPa, especially E > 4 GPa, like E > 5 GPa. In such embodiments, the optical fiber sensor (embedded in the encapsulant) may be relatively insensitive to pressure. Alternatively, E < 2 GPa may apply, such as E < 1.5 GPa, especially E < 1 GPa, (and e.g. E > 0.1 GPa). In such embodiments, the optical fiber sensor (embedded in the encapsulant) may be relatively sensitive to pressure. Hence, CTE > 40*1 O’6m / (m°C) and E > 2 GPa may apply, wherein the optical fiber sensor (embedded in the encapsulant) may be relatively sensitive to temperature, and relatively insensitive to pressure. Yet, CTE < 40*1 O’6m / (m°C) and E < 2 GPa may apply, wherein the optical fiber sensor (embedded in the encapsulant) may be relatively insensitive to temperature, and relatively sensitive to pressure.

[0092] As indicated above, the encapsulant may comprise a plastic (or polymeric material). For instance, the polymeric material may be selected from the group comprising a heat-curable polymeric material (i.e., a polymeric material forming crosslinks upon exposure to heat, e.g. a temperature of > 50 °C) and a light-curable polymeric material (i.e., a polymeric material forming crosslinks upon exposure to radiation, e.g. having a wavelength in the range of 350-420 nm). Further, the (heat-curable or light-curable) polymeric material may comprise one or more of an epoxy material and an acrylate material. For instance, the (light-curable) polymeric material may comprise an acrylate material, wherein the acrylate material may be selected from the group comprising a urethane acrylate, a polyester acrylate, an amino acrylate, and an epoxy acrylate. It should be noted that an epoxy acrylate may be an acrylate material, yet may also be an epoxy material. Further, the epoxy material may be an epoxy resin. Especially, in embodiments, the encapsulant may comprise an epoxy material, such as an epoxy resin. The epoxy (resin) material may comprise a hardening agent (or “hardener”). Further, the epoxy (resin) material may comprise a light-curing agent (e.g. a photo initiator or acrylate). The epoxy (resin) material may have a CTE of > 40*10"6m / (m°C), such as > 50*10"6m / (m°C), especially > 60* 10"6m / (m°C), like > 70* 10"6m / (m°C). Further, the epoxy (resin) material may have a Young’s modulus (E) of > 2 GPa, such as > 3 GPa, especially > 4 GPa, like > 5 GPa. In embodiments, the epoxy material may especially be a medical-grade epoxy material. Hence, in embodiments, the encapsulant may be a monolithic encapsulant, wherein the encapsulant may comprise an epoxy material. Especially, one or more may apply of: (i) the first encapsulant may comprise an epoxy material, wherein the first encapsulant may have an encapsulant shape selected from the group comprising an ellipsoid, a semi-ellipsoid, a cylinder, a cube, a (rectangular) cuboid, a pillow shape, and a truncated ellipsoid, and wherein the firstencapsulant may have an encapsulant volume (VE) selected from the range of 10-100 mm3; and (ii) the second encapsulant may comprise an epoxy material, wherein the second encapsulant may have an encapsulant shape selected from the group comprising an ellipsoid, a semi-ellipsoid, a cylinder, a cube, a (rectangular) cuboid, a pillow shape, and a truncated ellipsoid, and wherein the second encapsulant may have an encapsulant volume (VE) selected from the range of 10-100 mm3. An epoxy material may show relatively strong thermal expansion in the temperature range of 25-40 °C (such as 31-39 °C), thereby facilitating that such (first and / or second) encapsulants may protect the (first and / or second) optical fiber sensors against the influences of pressure, while sensitizing the (first and / or second) optical fiber sensors towards temperature (changes). Further, such an encapsulant shape may facilitate that the (first and / or second) encapsulant may have a relatively small equivalent circular diameter (DE) compared to the encapsulant length (LE), thereby facilitating threading the (first and / or second) encapsulant through a earner material (e.g. a textile), and / or minimizing the chance that a human (or animal) in contact with the earner may feel the (embedded) encapsulant (e.g. as a hard and / or sharp lump). Further yet, such an encapsulant volume (VE) may be large enough to provide a (first and / or second) encapsulant capable of withstanding bending under such pressures as applied on the (first and / or second) encapsulant during use of the sensing system, while being small enough to allow for a relatively fast and strong response of the (first and / or second) optical fiber sensors towards (changes in) temperature.

[0093] The (first and / or second) optical fiber arrangement having the encapsulant configurations, especially wherein the encapsulant may be a monolithic encapsulant, may be obtainable by an encapsulation method. The encapsulation method may comprise providing an optical fiber comprising an optical fiber sensor (e.g. an FBG). Further, the encapsulation method may comprise providing a mold. The mold may (when assembled) comprise a mold cavity having the encapsulant shape as described above. In embodiments, the mold may comprise a first slit and a second slit (i) configured (on opposite sides) in a side wall of the mold, and (ii) configured to host the optical fiber. As such, the encapsulation method may comprise placing part of the optical fiber in the mold cavity, wherein the optical fiber may extend from the mold via the first and second slits, and wherein the part of the optical fiber may comprise the optical fiber sensor. Alternatively, the mold may comprise a primary mold section and a secondary mold section defining the mold cavity (and removably coupled). As such, the encapsulation method may comprise placing part of the optical fiber in the mold cavity and between the primary and secondary mold sections, wherein the primary and secondary mold sections may be configured aligned, and wherein the part of the optical fibermay comprise the optical fiber sensor. The encapsulation method may further comprise exposing the optical fiber to a pre-strain selected from the range of > 2000 microstrains (ps), such as > 3000 ps, especially > 4000 ps (and e.g. up to 10000 ps). Further, the encapsulation method may comprise providing a (de-gassed) polymeric material (e.g. an epoxy material) to the mold cavity. The encapsulation method may especially comprise filling the mold cavity with the polymeric material. Further, the encapsulation method may comprise exposing the polymeric material to one or more of heat and radiation to provide a cured polymeric material. For instance, the encapsulation method may comprise exposing the polymeric material to one or more of (i) a temperature of > 50 °C, and (ii) light having a wavelength in the range of 350-420 nm. The encapsulation method may comprise removing the mold from the cured polymeric material, and removing the pre-strain from the optical fiber. Optionally, the encapsulation method may comprise smoothening the surface of the cured polymeric material (e.g. through sanding). Further, optionally, the encapsulation method may comprise exposing the cured polymeric material to one or more of heat and radiation to provide a double-cured polymeric material. For instance, the encapsulation method may comprise exposing the polymeric material to one or more of (i) a temperature of > 70 °C, and (ii) light having a wavelength in the range of 350-420 nm. Hence, the each of (i) the first optical fiber arrangement comprising the first encapsulant, and (ii) the second optical fiber arrangement comprising the second encapsulant may be obtainable by an encapsulation method, wherein the encapsulation method may comprise: (A) providing an optical fiber comprising an optical fiber sensor; (B) providing a mold (i) comprising a mold cavity having an encapsulant shape selected from the group comprising an ellipsoid, a semi-ellipsoid, a cylinder, a cube, a (rectangular) cuboid, a pillow shape, and a truncated ellipsoid and (ii) having a mold cavity volume (Vc) selected from the range as defined for the encapsulant volume (VE) as defined herein; wherein the mold may comprise (a) a first slit and a second slit (i) configured in a side wall of the mold, and (ii) configured to host the optical fiber, wherein the encapsulation method may comprise placing part of the optical fiber in the mold cavity, wherein the optical fiber may extend from the mold via the first and second slits, and wherein the part of the optical fiber may comprise the optical fiber sensor; or (b) a primary mold section and a secondary mold section defining the mold cavity, wherein the encapsulation method may comprise placing part of the optical fiber in the mold cavity and between the primary and secondary mold sections, wherein the part of the optical fiber may comprise the optical fiber sensor; (C) exposing the optical fiber to a pre-strain selected from the range of > 3000 ps; (D) providing a polymeric material to the mold cavity; (E) exposing the polymeric material to one or more of heat and radiation to provide a curedpolymeric material; and (F) removing the mold from the cured polymeric material, and removing the pre-strain from the optical fiber. Optionally, the encapsulation method may further comprise exposing the cured polymeric material to one or more of heat and radiation to provide a double-cured polymeric material.

[0094] In alternative embodiments, the first optical fiber sensor arrangement may comprise a first (non-elastic) support wire part. The first (non-elastic) support wire part may be configured mechanically coupled with the first optical fiber part. Especially, the first optical fiber part may be mechanically coupled with the first support wire part at the primary first anchoring point and the secondary first anchoring point. The first optical fiber part and the first support wire part may be configured mechanically coupled through one or more of gluing (e.g. with an epoxy, polyvinyl, or silicone glue), clamping, screwing, sewing, chemical bonding, melting together (including welding), and soldering. Further, the first optical fiber part may have a first optical fiber length Loi between the primary first anchoring point and the secondary first anchoring point. Additionally or alternatively, in embodiments, the first support wire part may have a first wire length Lwibetween the primary first anchoring point and the secondary first anchoring point. In embodiments, Lwi< Loi may apply, such as Lwi< 0.9*Loi, especially Lwi < 0.8*Loi. Additionally or alternatively, in embodiments, Lwi> 0.1*Loi may apply, such as Lwi > 0.2*Loi, especially Lwi> 0.3*Loi. Hence, in specific embodiments, the invention may provide the first optical fiber sensor arrangement, wherein the first optical fiber sensor arrangement may comprise a first support wire part, wherein the first optical fiber part may be mechanically coupled with the first support wire part at the primary first anchoring point and the secondary first anchoring point; wherein the first optical fiber part may have a first optical fiber length Loi between the primary first anchoring point and the secondary first anchoring point; wherein the first support wire part may have a first wire length Lwibetween the primary first anchoring point and the secondary first anchoring point; and wherein Lwi< Loi. Such a first support wire may prevent strain exerted on one or more of the support wire and the optical fiber outside of the primary first anchoring point and the secondary first anchoring point from being transferred to the first optical fiber sensor, thereby providing the benefit that only local forces may be measured with the first optical fiber sensor. Herein, embodiments relating to the first support wire part of the sensing system of the invention may apply mutatis mutandis to the first support wire part of the first optical fiber sensor arrangement of the invention.

[0095] Additionally or alternatively, the second optical fiber sensor arrangement may comprise a second (non-elastic) support wire part. The second (non-elastic) support wire part may be configured mechanically coupled with the second optical fiber part. Especially, thesecond optical fiber part may be mechanically coupled with the second support wire part at the primary second anchoring point and the secondary second anchoring point. The second optical fiber part and the second support wire part may be configured mechanically coupled through one or more of gluing (e.g. with an epoxy, polyvinyl, or silicone glue), clamping, screwing, sewing, chemical bonding, melting together (including welding), and soldering. Further, the second optical fiber part may have a second optical fiber length L02 between the primary second anchoring point and the secondary second anchoring point. Additionally or alternatively, the second support wire part may have a second wire length LW2 between the primary second anchoring point and the secondary second anchoring point. In embodiments, LW2 < L02 may apply, such as LW2 < 0.9*Lo2, especially LW2 < 0.8*Lo2. Additionally or alternatively, in embodiments, LW2 > O. L02 may apply, such as LW2 > 0.2*Lo2, especially LW2 > 0.3*LO2. Hence, in specific embodiments, one or more may apply of: (A) the first optical fiber sensor arrangement may comprise a first support wire part, wherein the first optical fiber part may be mechanically coupled with the first support wire part at the primary first anchoring point and the secondary first anchoring point; wherein the first optical fiber part may have a first optical fiber length L01 between the primary first anchoring point and the secondary first anchoring point; wherein the first support wire part may have a first wire length Lwibetween the primary first anchoring point and the secondary first anchoring point; wherein Lwi< 0.9*Loi; and (B) the second optical fiber sensor arrangement may comprise a second support wire part, wherein the second optical fiber part may be mechanically coupled with the second support wire part at the primary second anchoring point and the secondary second anchoring point; wherein the second optical fiber part may have a second optical fiber length L02 between the primary second anchoring point and the secondary second anchoring point; wherein the second support wire part may have a second wire length LW2 between the primary second anchoring point and the secondary second anchoring point; and wherein LW2 < L02. Hence, one or more of the first optical fiber sensor arrangement and the second optical fiber sensor arrangement may have a support-wire configuration. A support-wire configuration may prevent strain exerted on one or more of the support wire and the optical fiber outside of the primary and secondary first (and / or second) anchoring points from being transferred to the first (and / or second) optical fiber sensor, thereby providing the benefit that only local forces may be measured with the first (and / or second) optical fiber sensor.

[0096] Hence, the first optical fiber part may have the first optical fiber length L01, and the second optical fiber part may have the second optical fiber length L02. In embodiments, L01 and L02 may be individually selected from the range of > 1 cm, such as from the range of> 2 cm, especially from the range of > 3 cm. Additionally or alternatively, Loi and L02 may be individually selected from the range of < 20 cm, such as from the range of < 15 cm, especially from the range of < 10 cm. Hence, in embodiments, 1 cm < Loi < 20 cm may apply, such as 2 cm < Loi < 15 cm, especially 3 cm < Loi < 10 cm. Further, in embodiments, 1 cm < L02 < 20 cm may apply, such as 2 cm < L02 < 15 cm, especially 3 cm < L02 < 10 cm. Additionally or alternatively, the first wire length Lwiand the second wire length LW2 may be individually selected from the range of > 0.5 cm, such as from the range of > 1 cm, especially from the range of > 2 cm. Additionally or alternatively, Lwiand LW2 may be individually selected from the range of < 18 cm, such as from the range of < 13 cm, especially from the range of < 8 cm. Hence, in embodiments, 0.5 cm < Lwi< 18 cm may apply, such as 1 cm < Lwi< 13 cm, especially 2 cm < Lwi< 8 cm. Further, in embodiments, 0.5 cm < LW2 < 18 cm may apply, such as 1 cm < LW2 < 13 cm, especially 2 cm < LW2 < 8 cm.

[0097] In embodiments, the first and second support wire parts may be parts of the same support wire. That is, in embodiments, the sensing system (such as especially the carrier arrangement) may comprise a first support wire, wherein the first support wire may comprise the first support wire part and the second support wire part. Alternatively, the first and second support wire parts may be parts of different support wires. In such embodiments, the sensing system (such as especially the earner arrangement) may comprise a first support wire and a second support wire. Especially, the first support wire may comprise the first support wire part, and the second support wire may comprise the second support wire part. Hence, in specific embodiments, one of the following may apply: (A) the sensing system may comprise a first support wire, wherein the first support wire may comprise the first support wire part and the second support wire part; and (B) the sensing system may comprise a first support wire and a second support wire; wherein the first support wire may comprise the first support wire part; and wherein the second support wire may comprise the second support wire part. Mechanically coupling the first optical fiber part and the second optical fiber part to the same support wire may provide a sensing system with fewer components. Further, in embodiments wherein the first optical fiber part and the second optical fiber part are comprised by the same optical fiber, coupling both to a single support wire may provide an easier production method. Alternatively, mechanically coupling the first optical fiber part and the second optical fiber part to different support wires may provide more flexibility in the placement of the first optical fiber sensor and the second optical fiber sensor in the earner (arrangement).

[0098] The first (and / or second) support wire may be a flexible support wire. Further, the first (and / or second) support wire may be a non-elastic support wire. That is, the first(and / or second) support wire may be configured to stretch relatively little (along a length of the first (and / or second) support wire). In embodiments, the first (and / or second) support wire may be a cable. Further, the first (and / or second) support wire may be a plied support wire (such as a rope), with a ply (or number of twisted-together sub-wires) selected from the range of 1-14, such as 2-12, especially 3-10. Alternatively, the first (and / or second) support wire may be a chain or an articulated cable. That is, the first (and / or second) support wire may comprise a plurality of support wire elements, wherein the plurality of support wire elements may be configured interlocked or coupled together along a length direction of the support wire. In embodiments, the first (and / or second) support wire may comprise an optical fiber. Further, the first (and / or second) support wire may comprise a support wire material. The support wire material may be selected from the group comprising glass, polymers (e.g. nylon, polyester, etc.), metal, wood, cotton, wool, linen, and silk. The support wire may be comprised by the earner. Especially, the support wire may be a component of the earner. For instance, the support wire may be a thread in a mattress or mat. Further, the support wire may be configured (as a separate component from the earner, but configured) embedded in the earner. For instance, the support wire may be a separate optical fiber stretched through the carrier. Yet, in alternative embodiments, the support wire may be configured outside of the earner, yet may optionally be configured mechanically coupled to (and / or in physical contact with) the earner.

[0099] The first optical fiber sensor arrangement may have a first configuration selected from the group of the fixating-element configuration, the loop configuration, the encapsulant configuration, and the support-wire configuration. Further, the second optical fiber sensor arrangement may have a second configuration selected from the group of the fixating-element configuration, the loop configuration, the encapsulant configuration, and the supportwire configuration. In embodiments, the first configuration may be the same as the second configuration (i.e., the first optical fiber sensor arrangement and the second optical fiber sensor arrangement may have the same configuration). Further, the first configuration may be the same as the second configuration, yet the first optical fiber sensor arrangement and the second optical fiber sensor arrangement may differ in one or more of (i) the type of optical fiber sensor used, (ii) the material used for the optical fiber sensor, and (iii) the material used for one or more of the fixating element, the encapsulant, and the support wire. Alternatively, the first configuration may be different from the second configuration. Hence, in specific embodiments, the first optical fiber sensor arrangement may have a first configuration selected from the group of the fixating-element configuration, the loop configuration, the encapsulant configuration, and the support-wire configuration; and the second optical fiber sensor arrangement may havea second configuration selected from the group of the fixating-element configuration, the loop configuration, the encapsulant configuration, and the support-wire configuration, wherein one of the following may apply: (i) the first configuration is the same as the second configuration, and (ii) the first configuration is different from the second configuration. Selecting the same configuration for the first and second optical fiber sensor arrangements may provide the benefit that only one type of optical fiber sensor arrangement may need to be produced, and / or that the first optical fiber sensor and the second optical fiber sensor may have similar responses to the same stimuli. Alternatively, selecting the first configuration and the second configuration to be different may provide the benefit that the response of the first optical fiber sensor and the second optical fiber sensor may differ for one or more of the parameter types, thereby facilitating a more easy deconvolution of the optical response signal.

[0100] In embodiments, the first (and / or second) optical fiber sensor arrangement may have a configuration combining two (or more) of the fixating-element configuration, the loop configuration, the encapsulant configuration, and the support-wire configuration. For instance, the first (and / or second) optical fiber sensor arrangement may have a loop configuration fixated to a fixating element. Alternatively, the first (and / or second) optical fiber sensor arrangement may have an encapsulant configuration fixated to a fixating element (or comprised in a loop configuration). Further yet, the first (and / or second) optical fiber sensor arrangement may have a loop configuration fixated to a support wire. It will be clear to a person skilled in the art how the above-mentioned configurations may be combined to provide a suitable configuration. In embodiments wherein the first (and / or second) optical fiber sensor arrangement may have a configuration combining two (or more) of the fixating-element configuration, the loop configuration, the encapsulant configuration, and the support-wire configuration, the first (and / or second) optical fiber part may further comprise a tertiary first (and / or second) anchoring point and a quaternary first (and / or second) anchoring point. The tertiary first (and / or second) anchoring point and the quaternary first (and / or second) anchoring point may especially be used to fixate the optical fiber part according to the secondary configuration. For instance, the first optical fiber sensor arrangement may have a combination of the encapsulant configuration and the loop configuration, wherein the primary first anchoring point and the secondary first anchoring point may be used to fixate the first optical fiber part to the encapsulant, and wherein the tertiary first anchoring point and the quaternary first anchoring point may be mechanically coupled to provide the secondary (loop) configuration.

[0101] The system may execute a method or action in an “operational mode”. Likewise, in a method an action or step may be executed in an “operational mode”. This does not excludethat the system may also be adapted for providing another operational mode, or a plurality of other operational modes. Likewise, this may not exclude that before and / or after executing the operational mode one or more other operational modes may be executed. In embodiments, the control system may be adapted to provide at least the operational mode. Would other operational modes be available, the choice of such modes may be executed via a user interface, though executing an operational mode in dependence of a sensor signal or a (time) scheme may also be possible. The operational mode may also refer to a system that can only operate in a single operational mode (i.e. “on”, without further tunability).

[0102] The sensing system may have an operational mode. Especially, the sensing system may execute a method in the operational mode. Hence, according to a further aspect, the invention may provide a method for generating at least one output signal using the sensing system as defined herein. The method may especially comprise providing light source light (to one or more of the first optical fiber sensor and the second optical fiber sensor). Further, the method may comprise detecting(, in response to the light source light,) an optical response signal. The optical response signal may especially comprise one or more selected from the group of (i) a first optical response signal from the first optical fiber sensor, and (ii) a second optical response signal from the second optical fiber sensor. Additionally, the method may comprise determining at least two parameters based on the optical response signal. Further, the method may comprise deriving from the at least two parameters infoimation about one or more of: (i) a condition of the earner arrangement, or a change thereof, (ii) a condition in an environment surrounding the carrier arrangement, or a change thereof, and (iii) a condition of a human (or animal) in physical contact with the earner, or a change thereof. The method may further comprise generating at least one output signal based on the information. Hence, in specific embodiments, the invention may provide a method for generating at least one output signal using the sensing system as defined herein, wherein the method comprises: (a) providing light source light; (b) detecting an optical response signal, wherein the optical response signal comprises one or more selected from the group of (i) a first optical response signal from the first optical fiber sensor, and (ii) a second optical response signal from the second optical fiber sensor; (c) determining at least two parameters based on the optical response signal; (d) deriving from the at least two parameters information about one or more of: (i) a condition of the earner arrangement, or a change thereof, (ii) a condition in an environment surrounding the earner arrangement, or a change thereof, and (iii) a condition of a human in physical contact with the earner, or a change thereof; and (e) generating at least one output signal based on the information. Such a method may provide the benefit that the condition of (i) the earnerarrangement, (ii) the environment surrounding the carrier arrangement, and / or (iii) the human in physical contact with the earner, may be assessed with a non-invasive optical method, which may be relatively more safe for both a user and an operator (e.g. a caregiver). Further, such a method may especially provide a method for providing information to a user or operator based on an optical signal, such that the user or operator may perform an action based on the information to e.g. reduce risk of an injury, prevent a (skin) condition or injury, or reposition to improve posture. Further, such a method may provide users and / or operators with an update based on one or more health parameters (e.g. blood pressure or interval of ovulation). Herein, embodiments relating to the sensing system of the invention may also relate to the method of the invention. Similarly, embodiments relating to the method of the invention may also relate to the sensing system of the invention.

[0103] The method may comprise a step (a), comprising providing light source light. Especially, the method may comprise providing light source light with the light source of the sensing system. Hence, the light source light of the method may be the light source light of the sensing system. Embodiments relating to the light source light have been provided above with reference to the light source light of the sensing system. The light source light may comprise one or more of UV radiation, visible radiation, and IR radiation. Especially, the light source light may have a first peak wavelengthpi. In embodiments, 750 <pi< 950 nm may apply, such as 800 <pi< 900 nm, especially 825 <pi< 875 nm. Further, 1200 <pi< 1400 nm may apply, such as 1250 <pi< 1350 nm, especially 1275 <pi< 1325 nm. Further, 1450 <pi< 1650 nm may apply, such as 1500 <pi< 1600 nm, especially 1525 <pi< 1575 nm. The light source light may be injected into (or coupled into) one or more optical fibers of the sensing system. Alternatively, the light source may irradiate one or more of the n optical fiber sensors with the light source light from an external of the optical fiber. The method may comprise providing light source light to (at least) one or more of the first optical fiber sensor and the second optical fiber sensor. Especially, the n optical fiber sensors (of the sensing system) may comprise a first subset of x optical fiber sensors. In embodiments, x may be selected from the range of > 2, such as from the range of > 3, especially from the range of > 4. Additionally or alternatively, x may be selected from the range of < 200, such as from the range of < 100, especially from the range of < 50. Hence, in embodiments, the first subset may comprise 2-200, such as 3-100, especially 4-50, optical fiber sensors. In embodiments, x = n may apply. Yet, especially, x < n may apply. The x optical fiber sensors (of the first subset) may especially comprise (one or more of) the first optical fiber sensor and the second optical fiber sensor. Further, the first optical fiber sensor and the second optical fiber sensor may be (individually)selected from the group of FBGs and long-period fiber gratings. Especially, all of the x optical fiber sensors may be (individually) selected from the group of FBGs and long-period fiber gratings. In specific embodiments, the x optical fiber sensors may (all) be FBGs.

[0104] The method may further comprise a step (b), comprising detecting(, in response to the light source light,) an optical response signal. Especially, the method may comprise detecting the optical response signal with the detector of the sensing system. The optical response signal may comprise one or more of (i) a first optical response signal from the first optical fiber sensor, and (ii) a second optical response signal from the second optical fiber sensor. Further, the optical response signal may comprise an optical response signal from each of the x optical fiber sensors (of the first subset). The optical fiber sensor (providing the optical response signal) may be configured in a transmissive mode, wherein the light source light may be provided to a first end of the optical fiber sensor, and the method may comprise detecting the optical response signal from a second (opposite) end of the optical fiber sensor. Alternatively, the optical fiber sensor (providing the optical response signal) may be configured in a reflective mode, wherein the light source light may be provided to the first end of the optical fiber sensor, and the method may comprise detecting the optical response signal from the first end of the optical fiber sensor. Yet, in embodiments, the method may comprise detecting the optical response signal from both the first end and the second end of the optical fiber sensor.

[0105] The method may comprise a step (c), comprising determining at least two parameters based on the optical response signal. Further, the method may comprise determining y parameters based on the optical response signal (from the x optical fiber sensors of the first subset). In embodiments, y > 1 may apply, such as y > 2, especially y > 3. Additionally or alternatively, y < 10 may apply, such as y < 8, especially y < 5. Further, in embodiments, x > y may apply, such as x > (y+1), especially x > (y+2). Additionally or alternatively, x < (y+4) may apply, such as x < (y+3), especially x < (y+2). Determining the y parameters based on the optical response signal (of the x optical fiber sensors) may comprise determining a shift AXxof the first peak wavelength Xpiin the optical response signal from each of the x optical fiber sensors. That is, the optical response signal may be detected separately for each of the x optical fiber sensors, and the method may comprise determining a shift AXxof the first peak wavelengthpiin each optical response signal. Hence, the method may comprise determining a first shift A i in the optical response signal from a first optical fiber sensor (of the x optical fiber sensors), a second shift AX2 in the optical response signal from a second optical fiber sensor (of the x optical fiber sensors), and an xthshift AXxin the opticalresponse signal from the xthoptical fiber sensor (of the x optical fiber sensors). In embodiments, the shift AXxmay (for each optical fiber sensor) be related to the strain on the respective optical fiber sensor (as described above for the different type of optical fiber sensors).

[0106] Determining the y parameters may further comprise repeating, at multiple time points, steps (a) and (b) of the method for each of the x optical fiber sensors, to provide a time trace (AXx(t)) of the shift Axover time for each of the x optical fiber sensors. Additionally, the method may comprise decoupling y parameters from the x time traces (Ax(t)) (of the x optical fiber sensors) by solving the system of equations provided in Formula 1:

[0107] (1)-

[0108]

[0109] > >

[0110] In Formula 1, si and sxmay indicate a sensor transfer function for a first optical fiber sensor and the xthoptical fiber sensor of the x optical fiber sensors, respectively. Further, ki and kxmay indicate a parameter response sensitivity (i.e., a magnitude of the shift AXxper unit of the parameter) for the first optical fiber sensor and the xthoptical fiber sensor, respectively, and ri and rxmay indicate a parameter response time constant (indicating a time for the sensor’s step response to reach (1-)1A of its final value ) for the first optical fiber sensor and the xthoptical fiber sensor, respectively. Further, in Formula 1, the superscripts pl and py may indicate that the relevant value relates to a first parameter and an ythparameter of the y parameters, respectively, wherein pl (t) may indicate the time trace of the first parameter, and py (t) may indicate the time trace of the ythparameter. In Formula 1, the ellipses indicate that intermediate elements may be present in the matrix (e.g. in embodiments wherein x > 3 and y > 3), as is known to the person skilled in the art.

[0111] The system of equations represented by Formula 1 may provide a time trace for each of the y parameters. In embodiments, the method may further comprise determining the y parameters based on pl (t), ..., and py (t). That is, in embodiments wherein y = 3, the method may comprise determining the three parameters based on pl (t), p2 (t), and p3 (t). Hence, in specific embodiments, the first optical fiber sensor and the second optical fiber sensor may be selected from the group of fiber Bragg gratings and long-period fiber gratings; wherein the n optical fiber sensors may comprise a first subset of x optical fiber sensors; wherein the x optical fiber sensors may comprise the first optical fiber sensor and the second optical fiber sensor; wherein the light source light may have a first peak wavelengthpi; wherein the optical response signal may comprise an optical response signal from each of the x optical fiber sensors; wherein the method may comprise determining y parameters based on the opticalresponse signal, wherein x > y, wherein y > 2; wherein determining the y parameters based on the optical response signal may comprise: (i) determining a shift A / _xof the first peak wavelengthpiin the optical response signal from each of the x optical fiber sensors; (ii) repeating steps (a)-(b) (of the method) at multiple time points to provide, for each of the x optical fiber sensors, a time trace (Ax(t)) of the shift A / _xover time; (iii) decoupling y parameters from the x time traces (AXx(t)) by solving the system of equations of:

[0112] wherein si and sx

[0113]

[0114] >

[0115] may indicate the sensor transfer function for a first optical fiber sensor and an xthoptical fiber sensor of the x optical fiber sensors, respectively, wherein ki and kxmay indicate the parameter response sensitivity for the first optical fiber sensor and the xthoptical fiber sensor, respectively, wherein ri and rxmay indicate the parameter response time constant for the first optical fiber sensor and the xthoptical fiber sensor, respectively, wherein the superscripts pl and py may indicate that the relevant value relates to a first parameter and an ythparameter of the y parameters, respectively, wherein pl (t) may indicate the time trace of the first parameter, wherein py (t) may indicate the time trace of the ythparameter; and (iv) determining the y parameters based on pl (t), ..., and py (t). Such a method may provide the benefit that the effects of multiple parameters on the optical response signal may be decoupled from the (convoluted) optical response signal, thereby facilitating that the time traces for each parameter may be provided separately. Further, such a method may improve the accuracy of the result, as the contribution of each parameter to the optical response signal may be isolated.

[0116] The x optical fiber sensors may comprise the first optical fiber sensor and the second optical fiber sensor. Further, the optical response signal may comprise, such as especially consist of, the first optical response signal and the second optical response signal. As indicated above, the method may comprise determining at least two parameters based on the optical response signal. Here below, an embodiment is provided in which two parameters are determined from the optical response signal. Determining two parameters based on the optical response signal may comprise determining a first shift A i of the first peak wavelengthpiin the first optical response signal, and determining a second shift A / .2 of the first peak wavelengthpiin the second optical response signal. In embodiments, the first shift AXi and the second shift AX2 may be related to the strain on the first optical fiber sensor and the second optical fiber sensor, respectively. Further, determining the at least two parameters based on the optical response signal may comprise repeating steps (a)-(b) (of the method) at multiple timepoints to provide a first time trace (AXi (t)) of the first shift AXi over time (for the first optical fiber sensor), and a second time trace (AX2 (t)) of the second shift AX2 over time (for the second optical fiber sensor). In embodiments, the method may comprise decoupling a first parameter and a second parameter from the first time trace (A i (t)) and the second time trace (AX2 (t)) by solving the system of equations provided in Formula 2:

[0117] (2).

[0118]

[0119] In Formula 2, si and S2 may indicate the sensor transfer function for the first optical fiber sensor and the second optical fiber sensor, respectively. Especially, ki and k2 may indicate the parameter response sensitivity for the first optical fiber sensor and the second optical fiber sensor, respectively, and ri and 12 may indicate the parameter response time constant for the first optical fiber sensor and the second optical fiber sensor, respectively. Further, the superscripts pl and p2 may indicate that the relevant value may relate to the first parameter and the second parameter, respectively. In Formula 2, pl (t) may indicate the time trace of the first parameter, and p2 (t) may indicate the time trace of the second parameter. In embodiments, the method may comprise determining the (at least) two parameters based on pl (t) and p2 (t). Hence, in specific embodiments, the optical response signal may comprise the first optical response signal and the second optical response signal; and determining the at least two parameters based on the optical response signal may comprise: (i) determining a first shift A i of the first peak wavelength Xpiin the first optical response signal, and determining a second shift AX2 of the first peak wavelength Xpiin the second optical response signal; (ii) repeating steps (a)-(b) (of the method) at multiple time points to provide a first time trace (A i (t)) of the first shift AXi over time, and a second time trace (AX2 (t)) of the second shift AX2 over time; (iii) decoupling a first parameter and a second parameter from the first time trace (AXi (t)) and the second time trace (AX2 (t)) by solving the system of equations of:

[0120] wherein si and S2 may

[0121]

[0122] indicate the sensor transfer function for the first optical fiber sensor and the second optical fiber sensor, respectively, wherein ki and k2 may indicate the parameter response sensitivity for the first optical fiber sensor and the second optical fiber sensor, respectively, wherein ri and 12 may indicate the parameter response time constant for the first optical fiber sensor and the second optical fiber sensor, respectively, wherein the superscripts pl and p2 may indicate that the relevant value relates to the first parameter and the second parameter, respectively, wherein pl (t) may indicate the time trace of the first parameter, wherein p2 (t) may indicate the timetrace of the second parameter; and (iv) determining the at least two parameters based on pl (t) and p2 (t). Such a method for determining at least two parameters may provide the benefit that the contributions of the two parameters on the optical response signal of an optical fiber sensor may be decoupled, such that the information relating to both parameters may be provided separately (in the time traces pl (t) and p2 (t)).

[0123] As indicated above, the invention may provide a first optical fiber sensor arrangement. In such aspects of the invention, the invention may further provide a method for determining at least two parameters using the first optical fiber sensor arrangement as defined herein. The method may especially comprise providing light (to the first optical fiber sensor). In embodiments, the light provided to the first optical fiber sensor may have a peak wavelength selected from the range provided above for the first peak wavelength Xpi. Further, the light may especially be injected into (or coupled into) an optical fiber comprising the first optical fiber part (of the first optical fiber arrangement). In embodiments, the method may further comprise detecting (in response to the light) an optical response signal from the first optical fiber sensor. Especially, the first optical fiber sensor arrangement may be functionally coupled to a detector, wherein the detector may be configured to detect the optical response signal. In embodiments, the detector may be a spectrometer. The method (for determining at least two parameters using the first optical fiber sensor arrangement) may further comprise determining at least two parameters based on the optical response signal. Hence, in specific embodiments, (the invention may provide a first optical fiber sensor arrangement, wherein) the invention may (further) provide a method for determining at least two parameters using the first optical fiber sensor arrangement as defined herein, wherein the method may comprise: (a) providing light (to the first optical fiber sensor); (b) detecting an optical response signal from the first optical fiber sensor and (c) determining at least two parameters based on the optical response signal. Such a method may provide the benefit that multiple parameters may be determined using a single optical fiber sensor (arrangement). Hence, such a method may facilitate gathering information regarding multiple parameters with a relatively compact system.

[0124] The method (for determining at least two parameters using the first optical fiber sensor arrangement) may optionally further comprise deriving from the at least two parameters information about one or more of: (i) a condition in an environment surrounding the first optical fiber sensor arrangement, or a change thereof, and (ii) a condition of a human (or animal) in (direct or indirect) physical contact with the first optical fiber sensor arrangement, or a change thereof. In such embodiments, the first optical fiber sensor arrangement or the detector may be configured functionally coupled with a processing system (e.g. a control system or a computer).Further, in such embodiments, the method may further comprise generating at least one output signal based on the information.

[0125] In the method for determining at least two parameters using the first optical fiber sensor arrangement, the first optical fiber sensor may especially respond differently to the at least two parameters. As such, the at least two parameters may be decoupled by determining a first change A i and a second change A / .2 in the optical response signal. Further, determining the at least two parameters based on the optical response signal may comprise repeating the steps of providing light (to the first optical fiber sensor) and detecting an optical response signal at multiple time points to provide a first time trace (A i (t)) of the first change A i over time, and a second time trace (AX2 (t)) of the second change A 2 over time. In embodiments, the method may further comprise decoupling a first parameter and a second parameter from the first time trace (A i (t)) and the second time trace (A 2 (t)) by solving the system of equations provided in Formula 3:

[0126]

[0127] In Formula 3, si and S2 may indicate sensor transfer functions, ki and k may indicate parameter response sensitivities, and ri and 12 may indicate parameter response time constants. Further, the superscripts pl and p2 may indicate that the relevant value may relate to the first parameter and the second parameter, respectively. In Formula 3, pl (t) may indicate the time trace of the first parameter, and p2 (t) may indicate the time trace of the second parameter. The method may comprise determining the (at least) two parameters (from the optical response signal of a single first optical fiber sensor) based on pl (t) and p2 (t).

[0128] For instance, the first optical fiber sensor may comprise a birefringent optical fiber, such that the optical response signal from the first optical fiber sensor may comprise two (distinct) peaks. In such embodiments, both peaks may respond differently to changes in the at least two parameters (due to a difference in refractive index distribution in the waveguide core). For instance, a wavelength shift in response to the parameter change may differ for both peaks, or both peaks may differ in a change in peak intensity in response to the parameter change. Hence, for a first optical fiber sensor comprising a birefringent material, the at least two parameters may be decoupled by determining a difference in response between the two peaks. In such embodiments, the subscripts 1 in Formula 3 may indicate that the variables (Ak, s, k, and r) relate to the first peak, and the subscripts 2 may indicate that the variables relate to the second peak.Alternatively, the first optical fiber sensor may comprise a multicore waveguide core. That is, the waveguide core of the first optical fiber sensor may comprise more than one core. For instance, the first optical fiber sensor may comprise a triple helical core, wherein a first core may be a straight core configured along the center of the optical fiber, and wherein a second and third core may be configured twisting about the first core in a (double) helical configuration. Such a first optical fiber sensor may have directional sensing capabilities, as the response in each core may be different depending on the direction of the applied strain or pressure. Hence, the at least two parameters may, for such a first optical fiber sensor, be decoupled by determining a difference in response between at least two of the cores. In such embodiments, the subscripts 1 in Formula 3 may indicate that the variables (A , s, k, and r) relate to (an optical response signal from) a first core, and the subscripts 2 may indicate that the variables relate to (an optical response signal from) a second core.

[0129] Yet, in further embodiments, the first optical fiber sensor arrangement may comprise the first encapsulant, wherein the first encapsulant may comprise a first encapsulant first part and a first encapsulant second part. The first encapsulant first part may be configured encircling a first part of the first optical fiber sensor, and the first encapsulant second part may be configured encircling a second part of the first optical fiber sensor, wherein the first encapsulant first and second part may differ in one or more of the material used for the encapsulant (core and / or shell) and the configuration of the encapsulant (hollow or filled). Such a difference between the first encapsulant first part and the first encapsulant second part may facilitate that the first and second part of the first optical fiber sensor may respond differently to changes in (in at least one of) the at least two parameters, thereby facilitating that the at least two parameters may be decoupled from the optical response signal of the first optical fiber sensor. In such embodiments, the subscripts 1 in Formula 3 may indicate that the variables (AX, s, k, and r) relate to (an optical response signal from) the first part of the first optical fiber sensor, and the subscripts 2 may indicate that the variables relate to (an optical response signal from) the second part of the first optical fiber sensor.

[0130] Alternatively, the first optical fiber sensor arrangement may comprise the first encapsulant and / or the first (closed-shaped) fixating element. Especially, the first encapsulant and / or the first (closed-shaped) fixating element may be configured such, that for at least one parameter may apply that a first part of the first optical fiber sensor may be transduced in discrete levels (e.g. by using a transducer that may be mechanically moved in discrete positions under application of pressure), and a second part of the first optical fiber sensor may be transduced in a continuous level (while for another parameter both parts of the first opticalfiber sensor may be transduced in a continuous level). In such embodiments, the at least two parameters may be decoupled using the difference between the optical response signal from the first part of the first optical fiber part and the second part of the first optical fiber part.

[0131] In yet further embodiments, the first encapsulant and / or the first (closed-shaped) fixating element may be configured such, that the application of an external pressure (or strain) may result in a modulated optical response signal, while a change in temperature may result in a non-modulated optical response signal, such that the pressure and temperature parameters may be decoupled using a degree of modulation of the optical response signal.

[0132] In embodiments, decoupling at least two parameters from the optical response signal of a single optical fiber sensor may comprise obtaining a time trace of the optical response signal over time, wherein the at least two parameters may be decoupled by Fourier deconvolution of the time trace in the frequency domain. Such a method may be based on a relatively slower response time of the optical fiber sensor to changes in e.g. temperature, and a relatively faster response time of the optical fiber sensor to changes in e.g. pressure. Alternatively, machine learning may be used to decouple the at least two parameters, wherein the first optical fiber sensor may comprise a fiber Bragg grating, and a deep learning-based spectral segmentation model may be used to distinguish pressure and temperature variations by extracting fiber Bragg wavelength features from the optical response signal.

[0133] The method using the sensing system may comprise deriving from the at least two parameters information about one or more of: (i) a condition of the carrier arrangement, or a change thereof, (ii) a condition in an environment surrounding the earner arrangement, or a change thereof, and (iii) a condition of a human (or animal) in physical contact with the earner, or a change thereof. Further, the method using the first optical fiber sensor arrangement may comprise deriving from the at least two parameters information about one or more of: (i) a condition in an environment surrounding the first optical fiber sensor, or a change thereof, and (ii) a condition of a human (or animal) in (direct or indirect) physical contact with the first optical fiber sensor, or a change thereof. Especially, the information may comprise a(n absolute) pressure and / or a change in pressure. Additionally or alternatively, the information may comprise a(n absolute) temperature and / or a change in temperature. Additionally or alternatively, the information may comprise a (relative) humidity and / or a change in humidity. Additionally or alternatively, the information may comprise a(n absolute) strain and / or a change in strain. Yet, additionally or alternatively, the information may comprise a(n absolute) shear and / or a change in shear. Hence, in specific embodiments, the information may comprise one or more of a pressure, a change in pressure, a temperature, a change in temperature, ahumidity, a change in humidity, a strain, a change in strain, a shear, and a change in shear. Such information may be especially useful when assessing e.g. a risk of developing a pressure ulcers or an interval of ovulation. Further, such information may be useful to prevent e.g. overworking or overstretching of a recovering joint, or to assess a range of motion in a joint.

[0134] In embodiments, information regarding the change in one or more of (i) pressure, (ii) temperature, (iii) humidity, (iv) strain, and (v) shear may be obtained directly from the time traces pl (t) and p2 (t). Especially, the time traces pl (t) and p2 (t) may indicate a change in the relevant parameter over time. Further, information regarding a(n absolute) value of one of more of the pressure, temperature, (relative) humidity, strain, and shear may be obtained from each time point in the time traces pl (t) and p2 (t) using the sensor transfer function of the respective optical fiber sensor to the respective parameter. Yet, in embodiments, information regarding absolute values may be determined from > 2, such as > 3, especially > 4, time point of the time traces pl (t) and p2 (t). Additionally or alternatively, information regarding absolute values may be determined from < 200, such as < 150, especially < 100, time point of the time traces pl (t) and p2 (t). absolute values may be obtained from multiple time points using e.g. one of averaging, determining a moving average, splining, etc.. Such methods are known to the person skilled in the art. Using multiple time point to determine a(n absolute) value of one or more of the pressure, temperature, (relative) humidity, strain, and shear may provide the benefit that the accuracy of the obtained value(s) may be improved.

[0135] The method (using the sensing system as defined herein or the first optical fiber sensor arrangement as defined herein) may further comprise generating at least one output signal based on the information. Several embodiments relating to the output signal have been provided above for the sensing system. The at least one output signal may comprise a graph displaying the change in one or more parameters over time. Alternatively, the at least one output signal may comprise an absolute value for one or more of the parameters. Further, the at least one output signal may comprise a human risk score. The human risk score may especially be determined based on one or more of the (absolute) pressure, the change in pressure, the (absolute) temperature, the change in temperature, the (relative) humidity, the change in humidity, the (absolute) strain, the change in strain, the (absolute) shear, and the change in shear. For instance, the method may comprise determining if a line indicating a pressure over time for a human in contact with the earner (or first optical fiber sensor) may be located above a Gefen curve, wherein a pressure over time above the Gefen curve may indicate an increased risk of developing pressure ulcers (as is known to the person skilled in the art), and wherein the human risk score may be a risk score for developing a pressure ulcer.Additionally or alternatively, the method may comprise determining an increase in a relative temperature (of a human in contact with the earner or first optical fiber sensor) over a period of 24 hours, wherein an increase above a predetermined threshold may indicate an increased risk for pressure ulcers or a fever (e.g., due to an infection), and wherein the human risk score may be a risk score for developing a pressure ulcer or a fever.

[0136] Further, the human risk score may be determined by one or more additional parameters of the human in contact with the earner or the first optical fiber sensor, such as one or more of gender, age, height, weight, body mass index (BMI), systolic blood pressure, diastolic blood pressure, mean blood pressure, heart rate, respiratory rate, body temperature, oxygen saturation, medicine use, sedation scale, blood pH, partial pressure of oxygen in arterial blood (PaCh), partial pressure of carbon dioxide in arterial blood (PaCCh), lactate levels, creatinine levels, glucose levels, cholesterol levels, albumin levels, bilirubin levels, aspartate transferase (AST) levels, alanine transaminase (ALT) levels, white blood cell count, hemoglobin levels, Braden scale score, Waterlow scale score, and Norton (scale) score. Further, a health state of the human in contact with the earner or the first optical fiber sensor may be taken into account to determine the human risk score, such as if the human is suffering from one or more of diabetes, cerebrovascular disease, hypertension, arterial disease, and skin disease. Additionally, the human in contact with the earner or the first optical fiber sensor may be undergoing a therapy, such as one or more of invasive ventilation, continuous renal replacement therapy (CRRT), and extracorporeal membrane oxygenation (ECMO), which therapy may be taken into account to determine the human risk score. The one or more additional parameters may be determined using the sensing system of the invention, but may also be determined using (external) additional sensors. Further, the one or more additional parameters, health state, and therapy may be provided to (the control system of) the sensing system as user input data, wherein the method may comprise generating at least one output signal based on the information and the user input data. Hence, in specific embodiments, the at least one output signal may comprise a human risk score. The human risk score may especially indicate a susceptibility of the human in contact with the carrier or the first optical fiber sensor towards the development of adverse health effects (e.g. the development of a pressure ulcers or cognitive disease). Hence, an output signal comprising a human risk score may facilitate that a caregiver or user may adjust a treatment or monitoring plan based on the human risk score, to minimize the chance of the human developing an adverse health effect.

[0137] In alternative embodiments, the method may comprise predicting a risk of tissue damage based on at least one of the at least two parameters. The at least one parameter may bea pressure, wherein the method may comprise determining if a line indicating a pressure over time for a human in contact with the carrier (or first optical fiber sensor) may be located above a Gefen curve (see also above). Additionally or alternatively, the method may comprise determining an increase in a relative temperature (of a human in contact with the carrier or first optical fiber sensor) over a period of 24 hours, wherein an increase above a predetermined threshold may indicate an increased risk for pressure ulcers. In such embodiments, the at least one output signal may especially comprise a prediction output signal (for the risk of developing tissue damage). Hence, in specific embodiments, the method may comprise predicting a risk of tissue damage based on at least one of the at least two parameters, wherein the at least one output signal may comprise a prediction output signal. Using such a prediction output signal, a user or caregiver may start or adjust a treatment plan, such as e.g. cooling the human to decrease a temperature, providing medication to prevent infection, or repositioning (the human) to reduce a pressure. Hence, such a prediction output signal may facilitate preventing tissue damage, preferably before any symptoms occur.

[0138] As indicated above, the prediction output signal may be used to determine if a human in contact with the earner should be repositioned. Especially, in such embodiments, the earner may be the flexible human support. In specific embodiments, the earner may be one (or more) of a mattress and a cushion (or pillow), wherein the mattress may optionally be an inflatable mattrass or an alternating pressure mattress. The output signal may comprise the prediction output signal, based on which a caregiver may reposition a human in physical contact with the earner. Yet, in embodiments, the at least one output signal may comprise a prompt to change a position of the human in physical contact with the earner. Further, in embodiments, the at least one output signal may comprise a recommendation for a (new) positioning of the human. Hence, in specific embodiments, the carrier may be a flexible human support, wherein the at least one output signal may comprise a prompt to change a position of the human in physical contact with the carrier. An output signal comprising such a prompt may provide the benefit that a caregiver may not reposition the human (especially a patient) unnecessarily, which may cause irritation to the skin. Yet, an output signal comprising such a prompt may provide the benefit that the human may be repositioned in time to prevent the development of a skin condition (such as a pressure ulcer).

[0139] According to a further aspect, the invention may provide a system. The system may especially comprise an adjustable human support arrangement and the sensing system as defined herein. In embodiments, the adjustable human support arrangement may comprise the earner arrangement. In such embodiments, the earner may especially be a flexible humansupport. Further, the adjustable human support arrangement may comprise one or more adjustable elements. The one or more adjustable elements may be selected from the group comprising: (i) a cooling system configured to provide a cooling fluid through one or more cooling channels in the adjustable human support arrangement, (ii) a pressure control system configured to inflate or deflate one or more inflatable support elements in the adjustable human support arrangement, (iii) an actuator configured to adjust the height of one or more of a backrest and a footrest of the adjustable human support arrangement, and (iv) a ventilation system configured to control a flow of air from the earner arrangement to an interface between the earner and (the skin of) a human in contact with the earner. Especially, the control system (of the sensing system) may be configured to control at least one of the one or more adjustable elements based on the at least one output signal. Hence, in specific embodiments, the invention may provide a system, wherein the system comprises an adjustable human support arrangement and the sensing system as defined herein, wherein: (A) the adjustable human support arrangement comprises the earner arrangement, wherein the earner is a flexible human support; wherein the adjustable human support arrangement comprises one or more adjustable elements selected from the group comprising: (i) a cooling system configured to provide a cooling fluid through one or more cooling channels in the adjustable human support arrangement, (ii) a pressure control system configured to inflate or deflate one or more inflatable support elements in the adjustable human support arrangement, (iii) an actuator configured to adjust the height of one or more of a backrest and a footrest of the adjustable human support arrangement, and (iv) a ventilation system configured to control a flow of air from the earner arrangement to an interface between the earner and a human in contact with the earner; and (B) the control system is configured to control at least one of the one or more adjustable elements based on the at least one output signal. Such a system may provide the benefit that, would the at least one output signal indicate an increased risk of developing tissue damage, the control system may be configured to control at least one of the one or more adjustable elements to reduce the risk of developing said tissue damage. Further, such a system may provide the benefit that the system itself may prevent tissue damage, such that a caregiver may need to spend less time monitoring and repositioning a human in contact with the earner, and may have more time to focus on other caregiving tasks, thereby reducing a workload for the caregiver and improving a quality of care.

[0140] Hence, the system may comprise an adjustable human support arrangement. The adjustable human support arrangement may comprise, such as be, an adjustable bed. Yet, the adjustable human support arrangement may comprise, such as be, and adjustable (wheel)chair.Further, the adjustable human support arrangement may comprise the earner arrangement, such as especially the carrier. In such embodiments, the earner may be a flexible human support, such as selected from the group of a mattress and an cushion (or pillow). In embodiments, the n optical fiber sensors may especially be configured embedded in the carrier. Alternatively, the n optical fiber sensors may be configured at an interface between the earner and a human in physical contact with the earner. The adjustable human support arrangement may further comprise one or more adjustable elements. In embodiments, the one or more adjustable elements may comprise a cooling system. The cooling system may be configured to provide a cooling fluid through one or more cooling channels in the adjustable human support arrangement. In embodiments, the cooling fluid may be selected from the group comprising (ambient) air, nitrogen gas, carbon dioxide gas, sulfur hexafluoride gas, water, solutions of (ethylene, diethylene, or propylene) glycol and water, betaine, polyalkylene glycol, mineral oil, and silicone oil. Especially, the cooling fluid may be water. Further, the one or more cooling channels may be configured embedded in the earner. In such embodiments, the one or more cooling channels may especially be flexible cooling channels (e.g. made from rubber or silicone). Alternatively, the one or more cooling channels may be configured to support the earner (i.e., during use of the system, the one or more cooling channels may be configured below the earner). In such embodiments, the one or more cooling channels may be flexible channels or rigid channels (e.g. made from one or more metals). In further embodiments, the one or more cooling channels may be configured between the earner and the human in physical contact with the carrier, wherein the one or more cooling channels may especially be flexible channels. Yet especially, at least a first subset of the n optical fiber sensors may be configured between the one or more cooling channels and the human in physical contact with the earner.

[0141] In embodiments, the one or more adjustable elements may comprise a pressure control system. The pressure control system may be configured to inflate or deflate one or more inflatable support elements in the adjustable human support arrangement. In embodiments, the one or more inflatable support elements may comprise inflatable channels, wherein the inflatable channels may span (at least part of) a length and / or width of the carrier. Additionally or alternatively, the one or more inflatable support elements may comprise inflatable patches, wherein the inflatable patches may be configured to provide or reduce pressure in a small area in the earner. The pressure control system may be configured to inflate the one or more inflatable support elements with air, such as ambient air. Alternatively, the pressure control system may be configured to inflate the one or more inflatable support elements with a liquid, such as especially water. Such an inflatable support element may further be configured to coola skin of the human in contact with the earner. Hence, in embodiments, the pressure control system may comprise one or more of a pump and a fluid storage. The one or more of the pump and the fluid storage may be configured fluidically coupled with each of the one or more inflatable support elements (individually). Further, the pressure control system may comprise one or more valves, wherein each of the one or more valves may be configured to block a fluid flow to and / or from at least one of the inflatable support elements. The one or more inflatable support elements may be hollow, wherein a shell of the one or more inflatable support elements may comprise one or more of (natural and / or synthetic) rubber, silicone, (watertight and / or airtight) fabric, and a polymer film.

[0142] Additionally or alternatively, the one or more adjustable elements may comprise an actuator. The actuator may be configured to adjust the height of one or more of a backrest and a footrest of the adjustable human support arrangement. In embodiments, the adjustable human support arrangement may comprise a backrest (optionally comprising a headrest), a middle section, and a footrest, wherein: (i) the backrest may be configured to support a head and at least part of a torso of a human in physical contact with the earner, (ii) the middle section may be configured to support the pelvis and optionally at least part of the upper legs of the human in physical contact with the earner, and (iii) the footrest may be configured to support at least the feet (and optionally at least part of the lower and / or upper legs) of the human in physical contact with the earner. In embodiments, the actuator may be configured to adjust the height of one or more of the backrest and the footrest as a whole. Alternatively, the actuator may be configured to tilt the one or more of the backrest and the footrest with respect to the middle section. Especially, during use of the system, the actuator may be configured to tilt the backrest upwards with respect to the middle section (wherein the backrest and the middle section may remain in physical contact). Additionally or alternatively, during use of the system, the actuator may be configured to tilt the footrest (upwards or) downwards with respect to the middle section (wherein the footrest and the middle section may remain in physical contact). In embodiments, the backrest may comprise a headrest configured to support a head of the human in physical contact with the carrier, wherein the actuator may further be configured to tilt the headrest (upwards) with respect to (the remainder of) the backrest.

[0143] Further, the one or more adjustable elements may comprise a ventilation system. The ventilation system may be configured to control a flow of air from the earner arrangement to an interface between the earner and (the skin of) a human in contact with the earner. In embodiments, the earner may be an air-permeable earner, wherein the ventilation system may be configured to provide the flow of air from an underside of the earner, and wherein a(nopposite) topside of the earner may comprise (such as form) the interface between the carrier and the human. Alternatively, the ventilation system may comprise one or more ventilation elements, such as e.g. a grid of perforated or air-permeable channels, wherein the one or more ventilation elements may be configured at the interface between the earner and the human. Yet, in other embodiments, the one or more ventilation elements may be configured embedded in the earner. In embodiments, the ventilation system may comprise one or more of a pump and a fan, wherein the one or more of the pump and the fan may be configured to provide the flow of air (to the one or more ventilation elements).

[0144] The control system may be configured to control at least one of the adjustable elements based on the at least one output signal. For instance, the at least one output signal may comprise an alert that the pressure over time on one or more body parts of a human in contact with the earner exceeds the Gefen curve, wherein the control system may be configured to control the pressure control system to inflate one or more of the inflatable support elements to reduce the pressure on said one or more body parts. Alternatively, in such embodiments, the control system may be configured to control the actuator to adjust the height of the backrest and / or the footrest, thereby reducing the pressure on said body part. Alternatively, the at least one output signal may comprise a local (skin) temperature, wherein the local (skin) temperature may exceed a predetermined threshold, and wherein the control system may be configured to control the cooling system to provide a cooling fluid to the location of the increased temperature. In embodiments, the at least one output signal may comprise a local (skin) humidity, wherein the local (skin) humidity may exceed a predetermined threshold, and wherein the control system may be configured to control the ventilation system to provide a flow of air to the location of the increased humidity. Further, the at least one output signal may be related to a local (skin) condition of the human in contact with the earner, such as e.g. a local blood flow, wherein the control system may be configured to control the pressure control system to alternate the pressure on the skin, thereby improving a blood flow and preventing formation of, or promoting recovery of, tissue damage. Hence, the control system may be configured functionally, especially communicatively, coupled with one or more of the cooling system, the pressure control system, the actuator, and the ventilation system.

[0145] As indicated above, the at least one output signal may comprise a prediction output signal and / or a human risk score, wherein the prediction output signal and / or the human risk score may be a prediction of developing tissue damage (especially pressure ulcers) or a risk score indicating the risk of developing tissue damage (especially pressure ulcers). Further, the control system may be configured to control at least one of the one or more adjustableelements based on the at least one output signal. Especially, the control system may be configured to control at least one of the one or more adjustable elements to reduce a risk of developing tissue damage (especially pressure ulcers). Additionally, the control system may be configured to control at least one of the one or more adjustable elements to promote a recovery of tissue damage (especially pressure ulcers). Hence, in specific embodiments, the system may be a system for predicting, preventing formation of, and promoting recovery of tissue damage in a human (patient). Such a system may provide the benefit that (medical) costs relating to the treatment of tissue damage (especially pressure ulcers) may be reduced. Further, such a system may improve a health condition of a human (patient) by either preventing the formation of tissue damage or reducing the recovery time from tissue damage.

[0146] In a further aspect, the invention may provide a use of the sensing system as defined herein for one or more of (i) predicting, preventing formation of, and promoting recovery of pressure ulcers in a patient, (ii) measuring vital signs in a patient, (iii) estimating posture of a patient, (iv) estimating a range of motion in a joint of a patient, (v) measuring one or more of a recovery and a rehabilitation of a joint after a surgery, (vi) measuring early signs of cognitive diseases, (vii) monitoring a quality of sleep, and (viii) estimating an interval of ovulation. Additionally or alternatively, the invention may provide a use of the first optical fiber sensor arrangement as defined herein for one or more of (i) predicting, preventing formation of, and promoting recovery of pressure ulcers in a patient, (ii) measuring vital signs in a patient, (iii) estimating posture of a patient, (iv) estimating a range of motion in a joint of a patient, (v) measuring one or more of a recovery and a rehabilitation of a joint after a surgery, (vi) measuring early signs of cognitive diseases, (vii) monitoring a quality of sleep, and (viii) estimating an interval of ovulation. Additionally or alternatively, the invention may provide a use of the method as defined herein for one or more of (i) predicting, preventing formation of, and promoting recovery of pressure ulcers in a patient, (ii) measuring vital signs in a patient, (iii) estimating posture of a patient, (iv) estimating a range of motion in a joint of a patient, (v) measuring one or more of a recovery and a rehabilitation of a joint after a surgery, (vi) measuring early signs of cognitive diseases, (vii) monitoring a quality of sleep, and (viii) estimating an interval of ovulation. Further, the invention may provide a use of the system as defined herein for one or more of (i) predicting, preventing formation of, and promoting recovery of pressure ulcers in a patient, (ii) measuring vital signs in a patient, (iii) estimating posture of a patient, (iv) estimating a range of motion in a joint of a patient, (v) measuring one or more of a recovery and a rehabilitation of a joint after a surgery, (vi) measuring early signs of cognitive diseases, (vii) monitoring a quality of sleep, and (viii) estimating an interval ofovulation. Hence, in specific embodiments, the invention may provide a use of the sensing system as defined herein, the method as defined herein, and / or the system as defined herein, for one or more of (i) predicting, preventing formation of, and promoting recovery of pressure ulcers in a patient, (ii) measuring vital signs in a patient, (iii) estimating posture of a patient, (iv) estimating a range of motion in a joint of a patient, (v) measuring one or more of a recovery and a rehabilitation of a joint after a surgery, (vi) measuring early signs of cognitive diseases, (vii) monitoring a quality of sleep, and (viii) estimating an interval of ovulation. Such a use may improve a quality of life for a user and / or patient. Further, such a use may facilitate reducing medical costs related to e.g. the treatment of pressure ulcers, a cognitive disease, and / or insomnia.

[0147] Hence, the sensing system, method, and / or system as defined herein may be used to predict, prevent formation of, and promote recovery of pressure ulcers in a patient. Especially, the n optical fiber sensors may measure one or more parameters related to (an increased risk for) the formation of pressure ulcers, wherein the control system may provide information to e.g. a caregiver, or wherein the control system may control at least one adjustable element to prevent the formation of pressure ulcers. Further, the sensing system, method, and / or system as defined herein may be used to measure vital signs in a patient, such as especially by providing light to (at least one of) the n optical fiber sensors and detecting an optical response signal, wherein the optical response signal may be at least partially influenced by the vital signs. Further, the sensing system, method, and / or system as defined herein may be used to estimate posture of a patient. For instance, the n optical fiber sensors may determine a pressure on each of the n optical fiber sensors, wherein the control system may be configured to provide a 2D or 3D model of the human in contact with the carrier based on the relative pressures, and wherein the 2D or 3D model may be used to estimate a posture of the patient. Further, the sensing system, method, and / or system as defined herein may be used to estimate a range of motion in a joint of a patient. For instance, the earner may be a (flexible) wearable, wherein the patient may place the wearable around the joint, and wherein the sensing system may be configured to provide light source light and detect optical response signals while a patient rotates or moves the joint, such that the range of motion may be estimated from the optical response signals over the full movement of the joint. Further, the sensing system, method, and / or system as defined herein may be used to measure one or more of a recovery and a rehabilitation of a joint after a(n orthopedic) surgery. For instance, the sensing system may measure one or more of temperature and pressure to deteimine an elevated temperature of the joint (indicating infection and / or healing) and / or a pressure of the joint on the (wearable)earner (indicating swelling of the joint). Further, the sensing system, method, and / or system as defined herein may be used to measure early signs of cognitive diseases. For instance, the sensing system may be configured to measure a movement of the patient, wherein the movement may be a sign of the early onset of e.g. Parkinson’s disease. Further, the sensing system, method, and / or system as defined herein may be used to monitor a quality of sleep. For instance, the sensing system may be configured to measure one or more of an amount of movement during sleep, a body temperature during sleep, and an amount of sweating during sleep, wherein the quality of sleep may be measured based on the amount of movement, body temperature, and amount of sweating. Further, the sensing system, method, and / or system as defined herein may be used to estimate an interval of ovulation. Especially, the sensing system may be configured to deteimine a body temperature during the day, wherein the body temperature after awakening may be related to an ovulation cycle of the user.

[0148] The embodiments described herein are not limited to a single aspect of the invention. For example, an embodiment describing the method may, for example, further relate to the system, especially to an operational mode of the system, or especially to the control system. Similarly, an embodiment of the system describing an operation of the system may further relate to embodiments of the method. In particular, an embodiment of the method describing an operation (of the system) may indicate that the system may, in embodiments, be configured for and / or be suitable for the operation.

[0149] BRIEF DESCRIPTION OF THE DRAWINGS

[0150] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, and in which: Fig. 1 schematically depicts embodiments of the sensing system; Fig. 2 schematically depict embodiments of the first optical fiber sensor arrangement and the second optical fiber sensor arrangement; and Fig. 3 schematically depicts an embodiment of the system. The schematic drawings are not necessarily to scale.

[0151] DETAILED DESCRIPTION OF THE EMBODIMENTS

[0152] Fig. 1 schematically depicts an embodiment of the sensing system 1000. The sensing system 1000 may comprise a earner arrangement 6000, a light source 100, n optical fiber sensors 200, a detector 500, and a control system 300 (see Fig. IB). The earner arrangement 6000 may further comprise a earner 600. Especially, the earner 600 may be selected from a (flexible) wearable, a flexible human support, and bedding. Further, the lightsource 100 may be configured to provide light source light 101 (see Fig. 1A). In embodiments, the light source light 101 may comprise one or more of UV radiation, visible radiation, and IR radiation. The n optical fiber sensors 200 may comprise a first optical fiber sensor 210 and a second optical fiber sensor 220. Especially, the first optical fiber sensor 210 and the second optical fiber sensor 220 may be comprised by the earner arrangement 6000. Further, the n optical fiber sensors 200 may be configured in a light receiving relationship with the light source 100. In embodiments, the detector 500 may be functionally coupled to the n optical fiber sensors 200. Further, the detector 500 may be configured to detect (in response to the light source light 101 provided to one or more of the n optical fiber sensors 200) an optical response signal. Especially, the optical response signal may comprise one or more selected from the group of (i) a first optical response signal from the first optical fiber sensor 210, and (ii) a second optical response signal from the second optical fiber sensor 220. The control system 300 may be configured to determine at least two parameters based on the optical response signal. Especially, the at least two parameters may differ in parameter type. Further, the control system 300 may be configured to derive from the at least two parameters information about one or more of: (i) a condition of the earner arrangement 6000, or a change thereof, (ii) a condition in an environment surrounding the earner arrangement 6000, or a change thereof, and (iii) a condition of a human (or animal) in physical contact with the earner 600, or a change thereof. Additionally, the control system 300 may be configured to generate at least one output signal based on the information.

[0153] In figure IB, the light source 100 and the detector 500 are configured on the same end of the first optical fiber sensor 210 and second optical fiber sensor 220 (i.e., the first and second optical fiber sensors 210,220 are depicted in a reflective mode). In Fig. 1C, the light source 100 and the detector 500 are configured on opposite ends of the first optical fiber sensor 210 and second optical fiber sensor 220 (i.e., the first and second optical fiber sensors 210,220 are depicted in a transmissive mode). The earner 600 may comprise a flexible human support. Further, the earner 600 may comprise a first sensing region 601 and a second sensing region 602 (see Fig. IB). The first optical fiber sensor 210 may especially be configured embedded in the first sensing region 601. Further, the second optical fiber sensor 220 may be configured embedded in the second sensing region 602. One of the first and second sensing regions 601,602 may be configured closer to a face of the earner 600 than another of the first and second sensing regions 601,602. In such embodiments, the first and second sensing regions 601,602 may comprise a same earner material. Alternatively, as depicted in Fig. 1C, the earner 600 may comprise (a layer stack 605 comprising) a first sensing layer 610, a second sensinglayer 620, and a (human) skin contacting face 630. Especially, the (human) skin contacting face 630 may be comprised by either the first sensing layer 610 or the second sensing layer 620 (in Fig. 1C, the skin contacting face 630 is comprised by the first sensing layer 610). Further, the first optical fiber sensor 210 may be configured embedded in the first sensing layer 610. Additionally or alternatively, the second optical fiber sensor 220 may be configured embedded in the second sensing layer 620. The (layer stack 605 of) the earner 600 may further comprise a thermally insulating layer 650. The thermally insulating layer 650 may especially be configured between the first sensing layer 610 and the second sensing layer 620. Yet, in alternative embodiments, (the layer stack 605 of) the earner 600 may comprise a thermally conductive layer 660. In such embodiments, the thermally conductive layer 660 may especially be configured between the first sensing layer 610 and the second sensing layer 620.

[0154] The first sensing region 601 and the second sensing region 602 may be configured at least partially separated by (a third (sensing) region 603 comprising) a third earner material 6030. The third region 603 may be the thermally conductive or insulating layer 650,660, wherein the thermally conductive or insulating layer 650,660 may thus be configured between the first sensing region 601 and the second sensing region 602. The first sensing region 601 may comprise a first earner material 6010. Further, the second sensing region 602 may comprise a second carrier material 6020. The first and second earner materials 6010,6020 may be the same, yet may also differ. In a rest state of the earner 600, the first and second optical fiber sensor arrangements 2100,2200, such as the first and second sensor arrays, may be configured (spatially) separated by a shortest distance zi. As depicted in Figs. 1B-C, the shortest distance zi may especially be in a direction perpendicular to a face of the earner 600, such as perpendicular to the skin contacting face 630.

[0155] Further, in embodiments, the sensing system 1000 may comprise a first optical fiber sensor arrangement 2100 and a second optical fiber sensor arrangement 2200. The first and second optical fiber sensor arrangements 2100,2200 are depicted in a more detailed view in Fig. 1 A, where the dashed boxes indicate the (virtual) boundaries of the first optical fiber sensor arrangement 2100 and the second optical fiber sensor arrangement 2200, respectively. The first optical fiber sensor arrangement 2100 may comprise a first optical fiber part 2110. Further, the first optical fiber part 2110 may comprise the first optical fiber sensor 210, a primary first anchoring point 2111, and a secondary first anchoring point 2112. Especially, the primary first anchoring point 2111 and the secondary first anchoring point 2112 may be configured on either side of the first optical fiber sensor 210 (along the first optical fiber part 2110). Further, the primary first anchoring point 2111 and the secondary first anchoring point2112 may be configured to constrain a movement of (a part of) the first optical fiber part 2110 configured between the primary first anchoring point 2111 and the secondary first anchoring point 2112. Similarly, the second optical fiber sensor arrangement 2200 may comprise a second optical fiber part 2210. The second optical fiber part 2210 may especially comprise the second optical fiber sensor 220, a primary second anchoring point 2211, and a secondary second anchoring point 2212. Further, the primary second anchoring point 2211 and the secondary second anchoring point 2212 may be configured on either side of the second optical fiber sensor 220 (along the second optical fiber part 2210). Especially, the primary second anchoring point 2211 and the secondary second anchoring point 2212 may be configured to constrain a movement of (a part of) the second optical fiber part 2210 configured between the primary second anchoring point 2211 and the secondary second anchoring point 2212.

[0156] As schematically depicted in Fig. 1A(I), the sensing system 1000 may comprise a first optical fiber 1100, wherein the first optical fiber 1100 may comprise the first optical fiber part 2110 and the second optical fiber part 2210. Alternatively, as schematically depicted in Fig. 1A(I1), the sensing system 1000 may comprise a first optical fiber 1100 and a (separate) second optical fiber 1200. In such embodiments, the first optical fiber 1100 may comprise the first optical fiber part 2110. Further, the second optical fiber 1200 may comprise the second optical fiber part 2210. In embodiments wherein the first optical fiber 1100 may comprise the first and second optical fiber parts 2110,2210, the primary first anchoring point 2111, the secondary first anchoring point 2112, the primary second anchoring point 2211, and the secondary second anchoring point 2212 may be sequentially arranged along the first optical fiber 1100. The first optical fiber 1100 may have a first fiber length Li between the secondary first anchoring point 2112 and the primary second anchoring point 2211. Further, the secondary first anchoring point 2112 and the primary second anchoring point 2211 may be spatially separated (in the earner arrangement 6000) by a first distance di. In embodiments, di < 0.9*Li may apply.

[0157] Fig. 1 may further schematically depict an embodiment of the method for generating at least one output signal using the sensing system 1000 as defined herein. In embodiments, the method may comprise (a step (a) comprising) providing light source light 101 (to a first subset 20 of x optical fiber sensors 200 comprising the first optical fiber sensor 210 and the second optical fiber sensor 220). Further, the method may comprise (a step (b) comprising) detecting(, in response to the light source light 101,) an optical response signal. The optical response signal may especially comprise one or more selected from the group of (i) a first optical response signal from the first optical fiber sensor 210, and (ii) a second opticalresponse signal from the second optical fiber sensor 220. Additionally, the method may comprise (a step (c) comprising) determining at least two parameters based on the optical response signal. Further, the method may comprise (a step (d) comprising) deriving from the at least two parameters information about one or more of: (i) a condition of the earner arrangement 6000, or a change thereof, (ii) a condition in an environment surrounding the carrier arrangement 6000, or a change thereof, and (iii) a condition of a human (or animal) in physical contact with the earner 600, or a change thereof. Further yet, the method may comprise (a step (e) comprising) generating at least one output signal based on the information.

[0158] Fig. 2A schematically depicts a further embodiment of the sensing system 1000. The first optical fiber sensor arrangement 2100 may comprise a first closed-shaped fixating element (2120). The first closed-shaped fixating element 2120 may be configured encircling the first optical fiber sensor 210. Further, the first optical fiber part 2110 may be configured fixated to the first closed-shaped fixating element 2120 at the primary first anchoring point 2111 and the secondary first anchoring point 2112. In specific embodiments, the primary first anchoring point 2111 and the secondary first anchoring point 2112 may be configured on opposite sides of the first closed-shaped fixating element 2120. Additionally or alternatively, the second optical fiber sensor arrangement 2200 may comprise a second closed-shaped fixating element 2220. The second closed-shaped fixating element 2220 may be configured encircling the second optical fiber sensor 220. Further, the second optical fiber part 2210 may be configured fixated to the second closed-shaped fixating element 2220 at the primary second anchoring point 2211 and the secondary second anchoring point 2212. In embodiments, the primary second anchoring point 2211 and the secondary second anchoring point 2212 may be configured on opposite sides of the second closed-shaped fixating element 2220.

[0159] Especially, the first closed-shaped fixating element 2120 may have a closed curve-like shape (such as a circular shape). Additionally or alternatively, the second closedshaped fixating element 2220 may have a closed curve- 1 ike shape (such as a circular shape). Further, the first optical fiber sensor arrangement 2100 may comprise a first diaphragm 2125. The first diaphragm 2125 may be configured fixated to the first closed-shaped fixating element 2120 (around a circumference of the first closed-shaped fixating element 2120). Further, the first diaphragm 2125 may be configured covering the first optical fiber sensor 210. Additionally or alternatively, the second optical fiber sensor arrangement 2200 may comprise a second diaphragm 2225. The second diaphragm 2225 may be configured fixated to the second closed-shaped fixating element 2220 (around a circumference of the second closed-shapedfixating element 2220). Further, the second diaphragm 2225 may be configured covering the second optical fiber sensor 220.

[0160] Fig. 2B schematically depicts a further embodiment of the first optical fiber sensor arrangement 2100 and the second optical fiber sensor arrangement 2200. The primary first anchoring point 2111 and the secondary first anchoring point 2112 may be configured mechanically coupled, thereby forming a first loop 2130. The first loop 2130 may especially comprise the first optical fiber sensor 210. Additionally or alternatively, the primary second anchoring point 2211 and the secondary second anchoring point 2212 may be configured mechanically coupled, thereby forming a second loop 2230. The second loop 2230 may especially comprise the second optical fiber sensor 220. In embodiments, the first optical fiber sensor 210 may be configured (approximately) halfway between the primary first anchoring point 2111 and the secondary first anchoring point 2112 in the first loop 2130. Additionally or alternatively, the second optical fiber sensor 220 may be configured (approximately) halfway between the primary second anchoring point 2211 and the secondary second anchoring point 2212 in the second loop 2230.

[0161] Fig. 2C schematically depicts a further embodiment of the first optical fiber sensor arrangement 2100 and the second optical fiber sensor arrangement 2200. The first optical fiber sensor arrangement 2100 may comprise a first encapsulant 2140. The first encapsulant 2140 may be configured enclosing the first optical fiber sensor 210 (around a circumference of the first optical fiber sensor 210). Further, the first optical fiber part 2110 may be configured extending from the first encapsulant 2140 (on either side of the first encapsulant 2140). In embodiments, the first encapsulant 2140 may be configured fixated to at least part of the first optical fiber part 2110 (such as especially at the primary first anchoring point 2111 and the secondary first anchoring point 2112). Additionally or alternatively, the second optical fiber sensor arrangement 2200 may comprise a second encapsulant 2240. The second encapsulant 2240 may be configured enclosing the second optical fiber sensor 220 (around a circumference of the second optical fiber sensor 220). Further, the second optical fiber part 2210 may be configured extending from the second encapsulant 2240 (on either side of the second encapsulant 2240). In embodiments, the second encapsulant 2240 may be configured fixated to at least part of the second optical fiber part 2210 (such as especially at the primary second anchoring point 2211 and the secondary second anchoring point 2212). In specific embodiments, one or more of the first encapsulant 2140 and the second encapsulant 2240 may comprise a hollow metallic cylinder.Fig. 2D schematically depicts a further embodiment of the first optical fiber sensor arrangement 2100 and the second optical fiber sensor arrangement 2200. The first optical fiber sensor arrangement 2100 may comprise a first (non-elastic) support wire part 2150. Especially, the first optical fiber part 2110 may be mechanically coupled with the first support wire part 2150 at the primary first anchoring point 2111 and the secondary first anchoring point 2112. Further, the first optical fiber part 2110 may have a first optical fiber length Loi between the primary first anchoring point 2111 and the secondary first anchoring point 2112. Additionally, the first support wire part 2150 may have a first wire length Lwibetween the primary first anchoring point 2111 and the secondary first anchoring point 2112. In embodiments, Lwi< Loi may apply. Additionally or alternatively, the second optical fiber sensor arrangement 2200 may comprise a second (non-elastic) support wire part 2250. Especially, the second optical fiber part 2210 may be mechanically coupled with the second support wire part 2250 at the primary second anchoring point 2211 and the secondary second anchoring point 2212. Further, the second optical fiber part 2210 may have a second optical fiber length L02 between the primary second anchoring point 2211 and the secondary second anchoring point 2212. Additionally, the second support wire part 2250 may have a second wire length LW2 between the primary second anchoring point 2211 and the secondary second anchoring point 2212. In embodiments, LW2 < L02 may apply. The sensing system 1000 (especially the earner arrangement 6000) may comprise a first support wire 1300. In embodiments, the first support wire 1300 may comprise the first support wire part 2150 and the second support wire part 2250. Alternatively, the sensing system 1000 (especially the earner arrangement 6000) may comprise a first support wire 1300 and a second support wire 1400. In such embodiments, the first support wire 1300 may comprise the first support wire part 2150, and the second support wire 1400 may comprise the second support wire part 2250. As depicted in Fig. 2D, an anchoring point may be shared by multiple optical fiber sensor arrangements. For instance, the secondary first anchoring point 2112 of a primary first optical fiber sensor arrangement 2100 may be (or function as) the primary first anchoring point 2111 of a (neighboring) secondary first optical fiber sensor arrangement 2100.

[0162] Fig. 3 schematically depicts an embodiment of the system 5000 of the invention. The system 5000 may comprise an adjustable human support arrangement 5100 and the sensing system 1000 as defined herein. Especially, the adjustable human support arrangement 5100 may comprise the earner arrangement 6000. In such embodiments, the earner 600 may especially be a flexible human support. Further, the adjustable human support arrangement 5100 may comprise one or more adjustable elements 5110 selected from the group comprising:(i) a cooling system 5200 configured to provide a cooling fluid through one or more cooling channels 5210 in the adjustable human support arrangement 5100, (ii) a pressure control system 5300 configured to inflate or deflate one or more inflatable support elements 5310 in the adjustable human support arrangement 5100, (iii) an actuator 5400 configured to adjust the height of one or more of a backrest 5410 and a footrest 5420 of the adjustable human support arrangement 5100, and (iv) a ventilation system 5500 configured to control a flow of air from the earner arrangement 6000 to an interface between the earner 600 and (the skin of) a human in contact with the earner 600. Further, the control system 300 (of the sensing system 1000) may be configured to control at least one of the one or more adjustable elements 5110 based on the at least one output signal.

[0163] Fig. 4 schematically depicts an embodiment of the first and second optical fiber arrangements 2100,2200. The first and / or second encapsulant 2140,2240 may comprise an epoxy. Further, the first and / or second encapsulant 2140,2240 may have an encapsulant shape selected from the group comprising an ellipsoid (see Fig. 4(1)), a semi-ellipsoid (see Fig. 4(H)), a cylinder (see Fig. 4(111)), a cube, a cuboid (see Fig. 4(IV)), a pillow shape (see Fig. 4(V)), and a truncated ellipsoid (see Fig. 4(VI)). Additionally, the first and / or second encapsulant 2140,2240 may have an encapsulant volume VE selected from the range of 10-100 mm3.

[0164] Fig. 5 schematically depicts a further embodiment of the sensing system 1000, wherein the first sensing region 601 may comprise a first earner material 6010, and the second sensing region 602 may comprise a second carrier material 6020. Especially, the second earner material 6020 may be different from the first earner material 6010.

[0165] Experiments

[0166] Optical fiber sensor arrangements having the encapsulant configuration are prepared, and the temperature and pressure sensitivities of the optical fiber sensors 200 in the arrangements are determined. An optical fiber sensor arrangement comprising an epoxy material A as the encapsulant core, comprising a stainless steel (SS) tube as the encapsulant shell, and having a cylindrical encapsulant shape is used as a reference. Further, four optical fiber sensor arrangements having a monolithic encapsulant with a cuboid encapsulant shape, and comprising a mixture of epoxy material B and hardener H were prepared, wherein the optical fiber sensor arrangements differed in the amount of hardener H added to the epoxy material B. Additionally, two optical fiber sensor arrangements having a monolithic encapsulant with a pillow encapsulant shape, and comprising epoxy material C were prepared. For all optical fiber sensor arrangements, an FBG was used. An overview of the epoxy materials is provided in Table 1, and a summary of the optical fiber sensor arrangements isindicated in Table 2. For all epoxy materials, the properties listed - apart from the curing temperature Tc - correspond to the cured epoxy, wherein for epoxy material B a ratio B:H of 5:1 (v:v) was used.

[0167] Table 1 : overview of the epoxies used in the study. CTE = coefficient of thermal expansion, Tg = glass transition temperature, NA = data not available.

[0168] > >

[0169] >

[0170] > >

[0171]

[0172] Table 2: overview of the optical fiber sensor arrangements used in the study

[0173]

[0174] For all sensor arrangements with the exception of the SS tube, the following protocol is used to prepare the sensor arrangements. An optical fiber comprising an FBG is secured in place, and two molds (a top and bottom mold) are placed around the optical fiber, such that the FBG is enclosed by the molds. The optical fiber is subjected to a pre-strain of about 4100 microstrains (ps) (corresponding to a shift of 5 nm), and the epoxy (mixture) is injected into the molds. Prior to injection, air is removed from the epoxy (mixture). Mixtures of epoxy material B and hardener H are prepared fresh prior to injection. Next, sensor arrangements comprising B and H are cured at room temperature for 8 hours, and sensor arrangements comprising epoxy material C are cured at 105 °C for 4 hours. After curing, the molds are removed, the strain is removed from the optical fiber, excess epoxy material is removed, and the surfaces of the encapsulants are smoothened (e.g. by sanding) if needed. Then, the sensor arrangements are subjected to a second cure, wherein sensor arrangementscomprising epoxy material B and hardener H are cured at 70 °C for 4-6 hours, and sensor arrangements comprising epoxy material C are cured at 105 °C for 4 hours. Prior to testing, all sensor arrangements are integrated into a 3D-textile. Cuboid encapsulants are arranged flush with a surface of the 3D-textile (configured in contact with the heat source), while cylindrical and pillow encapsulants at arranged at or below the (same) surface of the 3D-textile.

[0175] For all sensor arrangements, the sensitivity of the sensor towards temperature Ts and pressure Ps is measured. Further, the response time rrtowards temperature changes is recorded, as well as the measurement error for temperature measurements (for both the sensor in isolation ei and the sensor integrated into the 3D-textile ec). Finally, the thermal stability ST of the sensor is determined, wherein the stability is indicated by the lowest temperature at which the sensor remains stable. The result of the measurements is shown in Table 3.

[0176] Table 3: measurement data for various optical fiber sensor arrangements. > > >

[0177]

[0178] As can be seen from Table 3, all sensor arrangements are stable up to at least 40 °C, such that the sensor arrangements may be used in applications where a human body temperature is measured. The sensor arrangements C (2 mm) and C (3 mm) are stable up to at least 80 °C, and may therefore further be able to withstand cleaning procedures at elevated temperatures (e.g. > 60 °C). Compared to the reference SS tube, all sensor arrangements have a higher temperature sensitivity Ts. As such, the sensor arrangements may allow the measurement of smaller changes in temperature, and / or the use of lower-resolution measurement equipment to read out the sensors. Further, as can be seen from Table 3, all sensor arrangements have a response time rrof < 35 s and measurement errors ei,ecof < 1°C, such that changes in temperature may be detected relatively quickly and accurately. Especially, sensor arrangements B, C (2 mm), and C (3 mm) samples may have measurement errors of < 0.33 °C when integrated into a carrier, allowing for even more accurate measurements. Further, all sensor arrangements have a pressure sensitivity Ps between -0.3 and 0.8 pm / kPa, such that anychange in a peak wavelength Xpof the optical signal recorded from the sensor may be (mostly) caused by a change in temperature, thereby allowing the selective measurement of the temperature.

[0179] The term “plurality” refers to two or more. The terms “substantially” or “essentially” herein, and similar terms, will be understood by the person skilled in the art. The terms “substantially” or “essentially” may also include embodiments with “entirely”, “completely”, “all”, etc. Hence, in embodiments the adjective substantially or essentially may also be removed. Where applicable, the term “substantially” or the term “essentially” may also relate to 90% or higher, such as 95% or higher, especially 99% or higher, even more especially 99.5% or higher, including 100%. The term “and / or” especially relates to one or more of the items mentioned before and after “and / or”. For instance, a phrase “item 1 and / or item 2” and similar phrases may relate to one or more of item 1 and item 2. The term "comprising" may refer to "consisting of' but may also refer to "containing at least the defined species and optionally one or more other species". The term “comprise” thus also includes embodiments wherein the term “comprises” means “consists of’.

[0180] Furthermore, the terms first, second, third, and the like, in the description and in the claims are used for distinguishing between similar elements and not necessarily for describing a sequential or chronological order, ft is to be understood that the terms so used are interchangeable under appropriate circumstances and that the embodiments of the invention described above are capable of operating in other sequences than described or illustrated herein.

[0181] The devices, apparatus, or systems may herein amongst others be described during operation. As will be clear to the person skilled in the art, the invention is not limited to methods of operation, or devices, apparatus, or systems in operation, ft should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim.

[0182] Use of the verb "to comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise”, “comprising”, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements.The invention may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In a device claim, or an apparatus claim, or a system claim, enumerating several means, several of these means may be embodied by one and the same item of hardware. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. In yet a further aspect, the invention (thus) provides a software product, which, when running on a computer is capable of bringing about (one or more embodiments of) the method as described herein.

[0183] The invention also provides a control system that may control the device, apparatus, or system, or that may execute the herein described method or process. Yet further, the invention also provides a computer program product, when running on a computer which is functionally coupled to or comprised by the device, apparatus, or system, controls one or more controllable elements of such device, apparatus, or system. The invention further applies to a device, apparatus, or system comprising one or more of the characterizing features described in the description and / or shown in the attached drawings. The invention further pertains to a method or process comprising one or more of the characterizing features described in the description and / or shown in the attached drawings.

[0184] The various aspects discussed in this patent can be combined in order to provide additional advantages. Further, the person skilled in the art will understand that embodiments can be combined, and that also more than two embodiments can be combined. Furthermore, some of the features can form the basis for one or more divisional applications.

Claims

CLAIMS:

1. A sensing system ( 1000) comprising a earner arrangement (6000), a light source (100), n optical fiber sensors (200), a detector (500), and a control system (300), wherein:the earner arrangement (6000) comprises a earner (600); wherein the earner (600) is a flexible human support; wherein the earner (600) comprises a first sensing region (601) and a second sensing region (602), wherein one or more applies of:a) (i) the first sensing region (601 ) comprises a first earner material (6010), and the second sensing region (602) comprises a second earner material (6020) different from the first earner material (6010); or (ii) one of the first sensing region (601) and the second sensing region (602) is configured closer to a face of the earner (600) than another of the first sensing region (601) and the second sensing region (602), wherein the first sensing region (601) and the second sensing region (602) comprise a same earner material; andb) the first sensing region (601) and the second sensing region (602) are configured at least partially separated by a third earner material (6030);the light source (100) is configured to provide light source light (101); wherein the light source light (101) comprises one or more of UV radiation, visible radiation, and IR radiation;the n optical fiber sensors (200) comprise a first optical fiber sensor (210) and a second optical fiber sensor (220), wherein the first optical fiber sensor (210) and the second optical fiber sensor (220) are comprised by the earner arrangement (6000); wherein the first optical fiber sensor (210) is configured embedded in the first sensing region (601), and wherein the second optical fiber sensor (220) is configured embedded in the second sensing region (602); wherein the n optical fiber sensors (200) are configured in a light receiving relationship with the light source (100);the detector (500) is functionally coupled to the n optical fiber sensors (200), and is configured to detect an optical response signal, wherein the optical response signal comprises (i) a first optical response signal from the first optical fiber sensor (210), and (ii) a second optical response signal from the second optical fiber sensor (220); andthe control system (300) is configured to (a) determine at least two parameters based on the optical response signal, wherein the at least two parameters differ in parameter type, wherein the parameter types are selected from the group comprising a pressure, atemperature, a humidity, a strain, and a shear; (b) derive from the at least two parameters information about one or more of: (i) a condition of the earner arrangement (6000), or a change thereof, and (ii) a condition of a human in physical contact with the earner (600), or a change thereof, and (c) generate at least one output signal based on the information.

2. The sensing system (1000) according to claim 1, wherein the at least two parameters relate to an absolute value of the parameter, or a change in the value of the parameter; and wherein the first optical fiber sensor (210) and the second optical fiber sensor (220) are individually selected from the group comprising a fiber Bragg grating, a microbend sensor, a polarimetric sensor, a distributed temperature sensor, a long-period fiber grating, a tapered optical fiber interferometer, a Fabry-Perot interferometer fiber, a fiber-optic Mach-Zehnder interferometer, a fiber-optic Michelson interferometer, a fiber-optic Sagnac interferometer, a surface plasmon resonance-based fiber-optic sensor, a fluorescence-based fiber-optic probe, a light diffuser-integrated optical fiber sensor, a multi-mode interference sensor, and a hollow fiber sensor.

3. The sensing system (1000) according to any one of the preceding claims, wherein the first sensing region (601) is a first sensing layer (610) within the earner (600), wherein the second sensing region (602) is a second sensing layer (620) within the earner (600); wherein the earner (600) comprises a skin contacting face (630); wherein the skin contacting face (630) is comprised by either the first sensing layer (610) or the second sensing layer (620).

4. The sensing system (1000) according to claim 3, wherein one of the following applies:the earner (600) comprises a thermally insulating layer (650), wherein the thermally insulating layer (650) is configured between the first sensing layer (610) and the second sensing layer (620); andthe earner (600) comprises a thermally conductive layer (660), wherein the thermally conductive layer (660) is configured between the first sensing layer (610) and the second sensing layer (620).

5. The sensing system (1000) according to any one of the preceding claims, wherein one or more applies of: (a) the first optical fiber sensor (210) and the second opticalfiber sensor (220) differ in a sensitivity towards one or more of the parameter types; (b) the control system (300) is configured to derive information about a condition of a human in physical contact with the earner (600), or a change thereof; and (c) the first optical fiber sensor (210) comprises a fiber Bragg grating; and the second optical fiber sensor (220) comprises a fiber Bragg grating.

6. The sensing system (1000) according to any one of the preceding claims, wherein the sensing system (1000) comprises a first optical fiber sensor arrangement (2100) and a second optical fiber sensor arrangement (2200); wherein:the first optical fiber sensor arrangement (2100) comprises a first optical fiber part (2110), wherein the first optical fiber part (2110) comprises the first optical fiber sensor (210), a primary first anchoring point (2111), and a secondary first anchoring point (2112); wherein the primary first anchoring point (2111) and the secondary first anchoring point (2112) are configured on either side of the first optical fiber sensor (210); and wherein the primary first anchoring point (2111) and the secondary first anchoring point (2112) are configured to constrain a movement of the first optical fiber part (2110) configured between the primary first anchoring point (2111) and the secondary first anchoring point (2112); andthe second optical fiber sensor arrangement (2200) comprises a second optical fiber part (2210), wherein the second optical fiber part (2210) comprises the second optical fiber sensor (220), a primary second anchoring point (2211), and a secondary second anchoring point (2212); wherein the primary second anchoring point (2211) and the secondary second anchoring point (2212) are configured on either side of the second optical fiber sensor (220); and wherein the primary second anchoring point (2211) and the secondary second anchoring point (2212) are configured to constrain a movement of the second optical fiber part (2210) configured between the primary second anchoring point (2211) and the secondary second anchoring point (2212).

7. The sensing system (1000) according to claim 6, wherein one of the following applies:the sensing system (1000) comprises a first optical fiber (1100), wherein the first optical fiber (1100) comprises the first optical fiber part (2110) and the second optical fiber part (2210); andthe sensing system (1000) comprises a first optical fiber (1100) and a second optical fiber (1200); wherein the first optical fiber (1100) comprises the first optical fiber part(2110); and wherein the second optical fiber (1200) comprises the second optical fiber part (2210).

8. The sensing system (1000) according to any one of claims 6-7, wherein one or more applies of:the first optical fiber sensor arrangement (2100) comprises a first closed-shaped fixating element (2120), wherein the first closed-shaped fixating element (2120) is configured encircling the first optical fiber sensor (210); wherein the first optical fiber part (2110) is configured fixated to the first closed-shaped fixating element (2120) at the primary first anchoring point (2111) and the secondary first anchoring point (2112); andthe second optical fiber sensor arrangement (2200) comprises a second closedshaped fixating element (2220), wherein the second closed-shaped fixating element (2220) is configured encircling the second optical fiber sensor (220); wherein the second optical fiber part (2210) is configured fixated to the second closed-shaped fixating element (2220) at the primary second anchoring point (2211) and the secondary second anchoring point (2212).

9. The sensing system (1000) according to any one of the preceding claims 6-8, wherein one or more applies of:the primary first anchoring point (2111) and the secondary first anchoring point (2112) are configured mechanically coupled, thereby forming a first loop (2130); andthe primary second anchoring point (2211) and the secondary second anchoring point (2212) are configured mechanically coupled, thereby forming a second loop (2230).

10. The sensing system (1000) according to any one of the preceding claims 6-9, wherein one or more applies of:the first optical fiber sensor arrangement (2100) comprises a first encapsulant (2140), wherein the first encapsulant (2140) is configured enclosing the first optical fiber sensor (210); wherein the first optical fiber part (2110) is configured extending from the first encapsulant (2140); and wherein the first encapsulant (2140) is configured fixated to at least part of the first optical fiber part (2110); andthe second optical fiber sensor arrangement (2200) comprises a second encapsulant (2240), wherein the second encapsulant (2240) is configured enclosing the second optical fiber sensor (220); wherein the second optical fiber part (2210) is configured extendingfrom the second encapsulant (2240); and wherein the second encapsulant (2240) is configured fixated to at least part of the second optical fiber part (2210).

11. The sensing system (1000) according to claim 10, wherein one or more applies of: (i) the first encapsulant (2140) comprises an epoxy material, wherein the first encapsulant (2140) has an encapsulant shape selected from the group comprising an ellipsoid, a semiellipsoid, a cylinder, a cube, a cuboid, a pillow shape, and a truncated ellipsoid, and wherein the first encapsulant (2140) has an encapsulant volume (VE) selected from the range of 10-100 mm3; and (ii) the second encapsulant (2240) comprises an epoxy material, wherein the second encapsulant (2240) has an encapsulant shape selected from the group comprising an ellipsoid, a semi-ellipsoid, a cylinder, a cube, a cuboid, a pillow shape, and a truncated ellipsoid, and wherein the second encapsulant (2240) has an encapsulant volume (VE) selected from the range of 10-100 mm3.

12. The sensing system (1000) according to any one of the preceding claims 6-11, wherein one or more applies of:the first optical fiber sensor arrangement (2100) comprises a first support wire part (2150), wherein the first optical fiber part (2110) is mechanically coupled with the first support wire part (2150) at the primary first anchoring point (2111) and the secondary first anchoring point (2112); wherein the first optical fiber part (2110) has a first optical fiber length Loi between the primary first anchoring point (2111) and the secondary first anchoring point (2112); wherein the first support wire part (2150) has a first wire length Lwibetween the primary first anchoring point (2111) and the secondary first anchoring point (2112); and wherein Lwi< Loi; andthe second optical fiber sensor arrangement (2200) comprises a second support wire part (2250), wherein the second optical fiber part (2210) is mechanically coupled with the second support wire part (2250) at the primary second anchoring point (2211) and the secondary second anchoring point (2212); wherein the second optical fiber part (2210) has a second optical fiber length L02 between the primary second anchoring point (2211) and the secondary second anchoring point (2212); wherein the second support wire part (2250) has a second wire length LW2 between the primary second anchoring point (2211) and the secondary second anchoring point (2212); and wherein LW2 < L02.

13. A method for generating at least one output signal using the sensing system (1000) according to any one of claims 1-12, wherein the method comprises:(a) providing light source light (101);(b) detecting an optical response signal, wherein the optical response signal comprises (i) a first optical response signal from the first optical fiber sensor (210), and (ii) a second optical response signal from the second optical fiber sensor (220);(c) determining at least two parameters based on the optical response signal;(d) deriving from the at least two parameters information about a condition of the carrier arrangement (6000), or a change thereof; and(e) generating at least one output signal based on the information.

14. The method according to claim 13, wherein the first optical fiber sensor (210) and the second optical fiber sensor (220) are selected from the group of fiber Bragg gratings and long-period fiber gratings; wherein the n optical fiber sensors (200) comprise a first subset (20) of x optical fiber sensors (200); wherein the x optical fiber sensors (2000) comprise the first optical fiber sensor (210) and the second optical fiber sensor (220); wherein the light source light (101) has a first peak wavelengthpi; wherein the optical response signal comprises an optical response signal from each of the x optical fiber sensors (200); wherein the method comprises determining y parameters based on the optical response signal, wherein x > y, wherein y > 2; wherein determining the y parameters based on the optical response signal comprises:(i) determining a shift Axof the first peak wavelengthpiin the optical response signal from each of the x optical fiber sensors (200);(ii) repeating steps (a)-(b) at multiple time points to provide, for each of the x optical fiber sensors (200), a time trace (Ax(t)) of the shift Axover time;(iii) decoupling y parameters from the x time traces (AXx(t)) by solving the system of equations of:wherein si and sxindicate a sensor>transfer function for a first optical fiber sensor (200) and an xthoptical fiber sensor (200) of the x optical fiber sensors (200), respectively, wherein ki and kxindicate a parameter response sensitivity for the first optical fiber sensor (200) and the xthoptical fiber sensor (200), respectively, wherein ri and rxindicate a parameter response time constant for the first opticalfiber sensor (200) and the xthoptical fiber sensor (200), respectively, wherein the superscripts pl and py indicate that the relevant value relates to a first parameter and an ythparameter of the y parameters, respectively, wherein pl (t) indicates the time trace of the first parameter, wherein py (t) indicates the time trace of the ythparameter; and(iv) determining the y parameters based on pl (t), ..., and py (t).

15. The method according to any one of claims 13-14, wherein one or more applies of: (i) the information comprises one or more of a pressure, a change in pressure, a temperature, a change in temperature, a humidity, a change in humidity, a strain, a change in strain, a shear, and a change in shear; and (ii) the at least one output signal comprises a prompt to change a position of the human in physical contact with the carrier (600).

16. A system (5000), wherein the system (5000) comprises an adjustable human support arrangement (5100) and the sensing system (1000) according to any one of claims 1- 12, wherein:the adjustable human support arrangement (5100) comprises the carrier arrangement (6000); wherein the adjustable human support arrangement (5100) comprises one or more adjustable elements (5110) selected from the group comprising: (i) a cooling system (5200) configured to provide a cooling fluid through one or more cooling channels (5210) in the adjustable human support arrangement (5100), (ii) a pressure control system (5300) configured to inflate or deflate one or more inflatable support elements (5310) in the adjustable human support arrangement (5100), (iii) an actuator (5400) configured to adjust the height of one or more of a backrest (5410) and a footrest (5420) of the adjustable human support arrangement (5100), and (iv) a ventilation system (5500) configured to control a flow of air from the earner arrangement (6000) to an interface between the carrier (600) and a human in contact with the earner (600); andthe control system (300) is configured to control at least one of the one or more adjustable elements (5110) based on the at least one output signal.

17. Use of the sensing system (1000) according to any one of claims 1-12, the method according to any one of claims 13-15, and / or the system (5000) according to claim 16, for one or more of (i) preventing formation of pressure ulcers in a patient, (ii) measuring vital signs in a patient, (iii) estimating posture of a patient, (iv) estimating a range of motion in a joint of a patient, (v) monitoring a quality of sleep, and (vi) estimating an interval of ovulation.

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