{"type": "FeatureCollection", "features": [{"id": "10.1117/12.2541767", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-19T16:17:34Z", "type": "Journal Article", "created": "2019-08-28", "title": "Utilising thermal annealing for multiplexing and sensitivity enhancement of polymer optical fibre sensors", "description": "Thermal annealing was initially introduced for multiplexing purposes, since it can induce a permanent negative Bragg wavelength shift for polymer fibre grating sensors. At a later stage, it is shown that annealing can also provide additional benefits, such as strain and humidity sensitivity enhancement and augmented temperature operational range. In this paper, we report additional usage of thermal annealing on PMMA fibre Bragg grating sensors. We show the possibility to tune Bragg wavelengths to longer wavelengths permanently by stretching the polymer optical fibre during the thermal annealing process. An array of sensors fabricated with only one phase-mask, demonstrates the concept by having Bragg wavelengths below and above the original inscribed spectral position. In addition, we report that thermal annealing can be also used to enhance the performance of sensors when used for stress and force monitoring.", "keywords": ["Fibers", "Plastic optical fibers", "Fiber optic sensors", "Polymers", "0103 physical sciences", "Engineering and Technology", "Electrical Engineering - Electronic Engineering - Information Engineering", "01 natural sciences", "Annealing"]}, "links": [{"href": "https://publications.aston.ac.uk/id/eprint/40228/1/enhancement_of_polymer_optical_fibre.pdf"}, {"href": "https://doi.org/10.1117/12.2541767"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Seventh%20European%20Workshop%20on%20Optical%20Fibre%20Sensors", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1117/12.2541767", "name": "item", "description": "10.1117/12.2541767", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1117/12.2541767"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2019-08-28T00:00:00Z"}}, {"id": "10.1117/12.2624440", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-19T16:17:34Z", "type": "Journal Article", "created": "2022-05-19", "title": "Perfluorinated polymer fibre Bragg grating sensors for distributed low-dose clinical X-ray measurements", "description": "Optical fibres have played an important role in the advancement of real-time dosimetry in clinical applications in recent years. Significant work has been done to increase precision and accuracy in detecting radiation doses during treatment, to avoid the negative effect that can ensue from irradiating healthy tissue around the tumour. The drive to develop distributed measurement in optical fibres has been limited to the slow scanning speed systems from optical time domain reflectometry (OTDR), however for radiotherapy dosimetry, with often short radiation pulse durations, fibre Bragg grating (FBG) interrogation is a better alternative because of the fast-scanning speed. The work presented here includes the preliminary results in the characterisation of CYTOP FBGs on exposure to X-ray radiation emitted from a clinical linear accelerator (linac) machine. A blue shifted linear response of the Bragg wavelength with sensitivity of 6.655 pm/Gy, 6.519 pm/Gy and 7.153 pm/Gy at the three main peaks (1522 nm, 1542 and 1561 nm), was recorded for a 9 Gy of radiation at a dose rate of 1.758 Gy/min with an amplitude fluctuation within the duration of radiation. The response demonstrates the potential for its use in low dose radiation dosimetry, providing for quasi-distributed sensing in radiotherapy.", "keywords": ["0211 other engineering and technologies", "fibre optics dosimetry", "02 engineering and technology", "Electrical Engineering - Electronic Engineering - Information Engineering", "X-ray", "Fibre Bragg grating", "Optical fibres", "Radiation Monitoring", "Dosimetry", "fibre Bragg grating sensors", "0202 electrical engineering", " electronic engineering", " information engineering", "fibre optics sensors", "Engineering and Technology", "CYTOP", "low-dose clinical X-ray measurements"]}, "links": [{"href": "https://doi.org/10.1117/12.2624440"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Micro-Structured%20and%20Specialty%20Optical%20Fibres%20VII", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1117/12.2624440", "name": "item", "description": "10.1117/12.2624440", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1117/12.2624440"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-05-19T00:00:00Z"}}, {"id": "10.1117/12.2624501", "type": "Feature", "geometry": null, "properties": {"license": "Open Access", "updated": "2026-09-19T16:17:34Z", "type": "Journal Article", "created": "2022-05-19", "title": "Pre-strain effects on CYTOP fibre Bragg grating temperature sensors", "description": "Cyclic transparent optical polymer (CYTOP) based fibre Bragg grating (FBG) sensors are of high interest recently due to their lower optical loss compared with the sensors fabricated in other polymeric materials, such as poly(methyl methacrylate). Numerous scientific reports have shown that polymer based FBGs are usually preferred over their silica counterparts due to their enhanced sensitivity to stress and pressure, and their affinity to humidity. Temperature monitoring with polymer FBGs is also extensively demonstrated, but with inconsistent results and non-linear responses, since most of the polymer optical fibres have a negative thermo-optic coefficient and positive thermal expansion coefficient that work to cancel out each other to some extent, resulting in mixed temperature sensitivities. In this work, an optical fibre with a CYTOP core and a Xylex cladding is used to investigate fibre pre-strain effects on the temperature sensitivity of FBG sensors. The sensors were placed in an environmental chamber with controlled temperature and relative humidity, and their response to temperature was evaluated under various fibre pre-strain values. Without any applied fibre strain, the thermal expansion coefficient slightly prevails over the thermo-optic effect, as a result the Bragg wavelength shifts in longer wavelengths. Under sufficient fibre strain, the thermal expansion coefficient is eliminated, and the temperature sensitivity is greatly enhanced, shifting the Bragg wavelength to shorter wavelengths. This paper demonstrates the possibility to have an array of Bragg grating sensors, some being temperature insensitive and some highly temperature sensitive along the same fibre.", "keywords": ["polymer optical fibre", "optical polymer", "fibre Bragg grating sensors", "0103 physical sciences", "Bragg gratings", "Engineering and Technology", "Electrical Engineering - Electronic Engineering - Information Engineering", "01 natural sciences", "temperature sensing"], "contacts": [{"organization": "Pospori, Andreas, Ioannou, Andreas, Kalli, Kyriacos,", "roles": ["creator"]}]}, "links": [{"href": "https://doi.org/10.1117/12.2624501"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Micro-Structured%20and%20Specialty%20Optical%20Fibres%20VII", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1117/12.2624501", "name": "item", "description": "10.1117/12.2624501", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1117/12.2624501"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-05-19T00:00:00Z"}}, {"id": "10.1117/12.2624516", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-19T16:17:34Z", "type": "Journal Article", "created": "2022-05-19", "title": "Plastic scintillator-based fibre dosimeters for measurement of X-ray pulses in a clinical setting", "description": "This work presents the development of plastic scintillator (BCF-10) based optical fibre sensors for medical radiotherapy dosimetry. Two different designs of BCF10 joined to PMMA (Polymethyl methacrylate) fibre were considered, based on simple Plug and Play designs for the rapid and effective assembly of radiation sensors. The first design was a simple butt-coupling arrangement sheathed in tubing, with an outer diameter of <2 mm. The second design explored the coupling joint of a cylindrical protrusion and hollow part of BCF10-PMMA that were achieved using femtosecond laser machining; the purpose of which was to maintain the original 1-mm fibre diameter for the sensor probe. The two fibres were pressed together and sealed with UV curing, hence the reference to a Plug and Play architecture. Both sensors exhibit higher output counts at the higher dose rate (due to the higher number of radiation pulses), although a discernible signal is observed at 50 MU/min for 6 MV, 15 MV energies and both sensors. When comparing both sensors with the different joint coupling designs, the flat surface connection of BCF-10 to PMMA demonstrates slightly higher photon counts compared with the micro-machined sensor (Plug n Play). However, the difference is small and the Plug n Play sensor benefits from the smaller sensor diameter (1 mm diameter), which is suitable for inserting into a small applicator or in-vivo monitoring. In the second section, micro-pulses of X-Ray radiation from Siemens Linear Accelerator (linac) were obtained and compared for two different energies and dose rates. Both of the sensors demonstrate the feasibility to be used for characterisation of X-ray pulses from a clinical linac.", "keywords": ["Plastic scintillator", "03 medical and health sciences", "0302 clinical medicine", "fibre dosimeters", "Engineering and Technology", "Electrical Engineering - Electronic Engineering - Information Engineering", "X-ray pulses"]}, "links": [{"href": "https://doi.org/10.1117/12.2624516"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Micro-Structured%20and%20Specialty%20Optical%20Fibres%20VII", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.1117/12.2624516", "name": "item", "description": "10.1117/12.2624516", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.1117/12.2624516"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-05-19T00:00:00Z"}}, {"id": "10.3390/s22197233", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-19T16:18:52Z", "type": "Journal Article", "created": "2022-09-26", "title": "Temperature and Humidity Sensitivity of Polymer Optical Fibre Sensors Tuned by Pre-Strain", "description": "<p>Polymer optical fibre Bragg grating (POFBG) sensors are of high interest due to their enhanced fracture toughness, flexibility in bending, and sensitivity in stress and pressure monitoring applications compared to silica-based sensors. The POFBG sensors can also detect humidity due to the hydrophilic nature of some polymers. However, multi-parameter sensing can cause cross-sensitivity issues in certain applications if the temperature and humidity measurements are not adequately compensated. In this work, we demonstrate the possibility of selectively tuning sensors\uffe2\uff80\uff99 temperature and humidity sensitivities to the desired level by applying a certain amount of fibre pre-strain. The temperature sensitivity of POFBG sensors fabricated in perfluoropolymers (CYTOP) can be selectively tuned from positive to negative values, having the option for insensitivity in specific temperature ranges depending on the amount of the applied pre-strain. The humidity sensitivity of sensors can also be changed from positive values to insensitivity. The importance of thermal annealing treatment of POFBG sensors for improved repeatability in temperature measurements is also reported. An array of 4 multiplexed POFBGs was fabricated, and each sensor was pre-strained accordingly to demonstrate the possibility of having targeted temperature and humidity sensitivities along the same fibre.</p>", "keywords": ["Chemical technology", "humidity", "temperature", "fibre Bragg gratings", "TP1-1185", "Electrical Engineering - Electronic Engineering - Information Engineering", "sensors", "sensitivity", "01 natural sciences", "Article", "polymer optical fibre", "0103 physical sciences", "Engineering and Technology", "XYLEX", "polymer optical fibre; fibre Bragg gratings; sensors; temperature; humidity; sensitivity; CYTOP; XYLEX", "CYTOP"]}, "links": [{"href": "http://www.mdpi.com/1424-8220/22/19/7233/pdf"}, {"href": "https://www.mdpi.com/1424-8220/22/19/7233/pdf"}, {"href": "https://doi.org/10.3390/s22197233"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Sensors", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/s22197233", "name": "item", "description": "10.3390/s22197233", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/s22197233"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-09-23T00:00:00Z"}}, {"id": "10.3390/s23010039", "type": "Feature", "geometry": null, "properties": {"updated": "2026-09-19T16:18:52Z", "type": "Journal Article", "created": "2022-12-21", "title": "Online Gamma Radiation Monitoring Using Few-Mode Polymer CYTOP Fiber Bragg Gratings", "description": "<p>We investigated the gamma radiation response of fiber Bragg gratings (FBGs) inscribed in a few-mode polymer optical fiber. The fiber had a graded-index CYTOP core of 20 \uffc2\uffb5m and XYLEX overclad of 250 \uffc2\uffb5m in diameter. Four FBGs were exposed to gamma radiation during four irradiation sessions at a 5.3 kGy/h dose rate. The FBGs showed a linear Bragg wavelength shift with the received dose with a mean sensitivity of \uffe2\uff88\uff923.95 pm/kGy at 43 \uffc2\uffb0C. The increased temperature provides a rise in the sensitivity: it reached \uffe2\uff88\uff9210.6 pm/kGy at 58 \uffc2\uffb0C. After irradiation, the FBGs showed partial recovery, which increased with the received dose. Furthermore, the FBG\uffe2\uff80\uff99s reflection power decreased with the dose. This attenuation is mainly due to insertion losses caused by the radiation induced attenuation in the CYTOP fiber. Linear response to the received dose makes CYTOP FBGs attractive for gamma radiation dosimetry. However, temperature dependence of the sensitivity should be compensated in practical applications.</p>", "keywords": ["Chemical technology", "gamma radiation", "polymer perfluorinated fiber", "TP1-1185", "02 engineering and technology", "Electrical Engineering - Electronic Engineering - Information Engineering", "01 natural sciences", "Article", "polymer optical fiber", "0103 physical sciences", "0202 electrical engineering", " electronic engineering", " information engineering", "Engineering and Technology", "fiber Bragg gratings", "polymer optical fiber; gamma radiation dosimetry; fiber Bragg gratings; gamma radiation; CYTOP; polymer perfluorinated fiber", "gamma radiation dosimetry", "CYTOP"]}, "links": [{"href": "http://www.mdpi.com/1424-8220/23/1/39/pdf"}, {"href": "https://www.mdpi.com/1424-8220/23/1/39/pdf"}, {"href": "https://doi.org/10.3390/s23010039"}, {"rel": "related", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/Sensors", "name": "related record", "description": "related record", "type": "application/json"}, {"rel": "self", "type": "application/geo+json", "title": "10.3390/s23010039", "name": "item", "description": "10.3390/s23010039", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items/10.3390/s23010039"}, {"rel": "collection", "type": "application/json", "title": "Collection", "name": "collection", "description": "Collection", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main"}], "time": {"date": "2022-12-21T00:00:00Z"}}], "links": [{"rel": "self", "type": "application/geo+json", "title": "This document as GeoJSON", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Electrical+Engineering+-+Electronic+Engineering+-+Information+Engineering&f=json", "hreflang": "en-US"}, {"rel": "alternate", "type": "text/html", "title": "This document as HTML", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Electrical+Engineering+-+Electronic+Engineering+-+Information+Engineering&f=html", "hreflang": "en-US"}, {"rel": "collection", "type": "application/json", "title": "Collection URL", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main", "hreflang": "en-US"}, {"type": "application/geo+json", "rel": "first", "title": "items (first)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Electrical+Engineering+-+Electronic+Engineering+-+Information+Engineering&", "hreflang": "en-US"}, {"rel": "last", "type": "application/geo+json", "title": "items (last)", "href": "https://repository.soilwise-he.eu/cat/collections/metadata:main/items?keywords=Electrical+Engineering+-+Electronic+Engineering+-+Information+Engineering&offset=6", "hreflang": "en-US"}], "numberMatched": 6, "numberReturned": 6, "distributedFeatures": [], "timeStamp": "2026-09-20T13:45:53.783083Z"}