Kort Bremer's research while affiliated with Leibniz Universität Hannover and other places
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Publications (64)
We report on a novel bend sensor with high flexibility and elasticity based on Bragg grating structures in polymer optical fibers to detect bending for the measurement of movement. The concept is very simple and relies on the inscription of eccentrical Bragg gratings into multimode graded-index polymer optical fibers via contact exposure with a kry...
The last decade has seen rapid developments in the areas of carbon fiber technology, additive manufacturing technology, sensor engineering, i.e., wearables, and new structural reinforcement techniques. These developments, although from different areas, have collectively paved way for concrete structures with non-corrosive reinforcement and in-built...
Optics and photonics are among the key technologies of the 21st century and offer the potential for novel applications in areas as diverse as sensing and spectroscopy, analytics, monitoring, biomedical imaging and diagnostics, as well as optical communication technology, among others [...]
The paper presents an evaluation on the structural and operational potential of fiber optic sensors (FOSs) to be utilized for real-time continuous structural health monitoring (SHM) of fiber-reinforced carbon concrete composites (C3).
We present a novel bend sensor based on eccentric fibre Bragg gratings in multimode graded-index polymer optical fibres. Dependent on number, position and depth of the gratings, 1D and 3D bend measurements are demonstrated.
The work presents an investigation on the utilization of an etched Graded-Index (GI)- Multi-Mode Fiber (MMF) for mode-multiplexed Fiber Optic Sensor (FOS) applications and the simultaneous measurement of the Surrounding Refractive Index (SRI) and temperature.
An all-optical plasmonic sensor platform designed for smartphones based on planar-optical waveguide structures integrated in a polymer chip is reported for the first time. To demonstrate the applicability of the sensor system for biosensing purposes, the detection of 25-hydroxyvitamin D (25OHD) in human serum samples using an AuNP-enhanced aptamer-...
We present a surface plasmon resonance (SPR) biosensor that is based on a planar-optical multi-mode (MM) polymer waveguide structure applied for the detection of biomolecules in the lower nano-molar (nM) range. The basic sensor shows a sensitivity of 608.6 nm/RIU when exposed to refractive index changes with a measurement resolution of 4.3 × 10−3 R...
An investigation on the feasibility of utilizing Mode Division Multiplexing (MDM) for simultaneous measurement of Surrounding Refractive Index (SRI) and temperature using a single sensor element based on an etched OM4 Graded Index Multi Mode Fiber (GI-MMF) with an integrated fiber Bragg Grating (BG), is presented. The proposed work is focused on th...
Detection of the small molecule 25-hydroxyvitamin D (25(OH)D) as the most relevant marker for vitamin D supply suffers from a high variability of results using the current detection methods, such as high-performance liquid chromatography (HPLC) and immunoassays. A new detection approach using a highly specific aptamer directed against 25(OH)D was e...
A SENSOR FOR COMBINED TEMPERATURE, PRESSURE, AND REFRACTIVE INDEX DETECTION
The paper presents an investigation into the durability of functionalized carbon structures (FCS) in a highly alkaline concrete environment. First, the suitability of optical fibers with different coatings—i.e., acrylate, polyimide, or carbon—for the FCS was investigated by subjecting fibers with different coatings to micro/macro bending and a 5% s...
To keep pace with the increasing demand of transmission capacity, space division multiplexing technologies are currently intensively investigated. In this context, mode selective glass fiber couplers are of great interest due to their compatibility with existing glass fiber networks. In this work, we present a novel type of mode selective glass fib...
An Optical Frequency Domain Reflectometry (OFDR) based fiber optic sensor scheme “embedded” in concrete for the purpose of structural health monitoring (SHM) of carbon concrete composites (C3) is presented. The design, while strengthening the concrete structure, also aims to monitor common SHM parameters such as strain and cracks. This was achieved...
In this work we investigate the strain, temperature and humidity sensitivity of a Fiber Bragg Grating (FBG) inscribed in a near infrared low-loss multimode perfluorinated polymer optical fiber based on cyclic transparent optical polymer (CYTOP). For this purpose, FBGs were inscribed into the multimode CYTOP fiber with a core diameter of 50 µm by us...
Long-period fiber gratings (LPGs) are well known for their sensitivity to external influences, which make them interesting for a large number of sensing applications. For these applications, fibers with a high numerical aperture (i.e., fibers with highly germanium (Ge)-doped fused silica fiber cores) are more attractive since they are intrinsically...
A key challenge for using multimode fibers for optical data transmission lies in the development of efficient mode-selective fiber couplers. Here, we present a novel and easy-to-implement process for their realization and first experimental results.
Optical fiber-based sensors “embedded” in functionalized carbon structures (FCSs) and textile net structures (TNSs) based on alkaline-resistant glass are introduced for the purpose of structural health monitoring (SHM) of concrete-based structures. The design aims to monitor common SHM parameters such as strain and cracks while at the same time act...
The accurate determination of physico-chemical fluid parameters is of major importance in many process engineering applications. Not only the monitoring of the phase distribution in piping systems but also the detection of chemical concentrations in liquids is of interest for an efficient, safe and reliable operation of laboratory as well as indust...
In this chapter we present more specific fibre types for particular applications. Starting with the multi-core fibre, which can be used as a substitution for ordinary SI-POF transmission fibres, but with better bending losses, over the ever increasing range of micro-structured POF for diverse sensing applications to fibres for illumination purposes...
In this work different fibre optic sensors for the structural health monitoring of civil engineering structures are reported. A fibre optic crack sensor and two different fibre optic moisture sensors have been designed to detect the moisture ingress in concrete based building structures. Moreover, the degeneration of the mechanical properties of op...
Optical fiber sensors have reached a high state of maturity. Besides the high number of sensor groups, multi-mode fiber evanescent field sensors can be found in a lot of applications. Here, the signal source commonly excites many optical modes under steady-state conditions. Perturbations of the fiber then produce leaky modes. Thus, a simple intensi...
Measurements of the rate of corrosion in concrete sewers need to take into consideration the humidity in the environment and thus its accurate measurement becomes critically important. Introducing a novel approach to do so, tailored Fiber Bragg grating (FBG)-based humidity sensors have been evaluated in situ to examine their durability, time respon...
An optical waveguide based surface plasmon resonance (SPR) sensor system for smartphones is presented. Future implementations of the sensor system could be integrated in the smartphone cover or used as low-cost, disposable diagnostic platform.
Spatial division multiplexing (SDM) in the form of mode division multiplexing (MDM) in multi-mode (MM) waveguides is currently explored to overcome the capacity limitation of single-mode (SM) waveguides in data transmission technology. In this work a new approach towards mode selective optical waveguide couplers to multiplex and demultiplex individ...
In this paper multiple-input multiple-output (MIMO) signal processing is investigated for fibre optic sensor applications. A (2 × 2) MIMO implementation is realized by using lower-order and higher-order mode groups of a graded-index (GI) multi-mode fibre (MMF) as separate transmission channels. A micro-bending pressure sensor changes these separate...
A simple continuous fabrication process for graded-index polymer optical fibers is presented that does not rely on dopants to form the refractive-index profile. A conventional melt-spinning process is followed by rapid cooling. This will result in a density gradient and finally in a refractive-index profile.
A fibre optic surface plasmon resonance (SPR) sensor system for smartphones is reported, for the first time. The sensor was fabricated by using an easy-to-implement silver coating technique and by polishing both ends of a 400 µm optical fibre to obtain 45° end-faces. For excitation and interrogation of the SPR sensor system the flash-light and came...
In this work, the compact all-fibre linear Erbium (Er)-doped fibre lasers, operating at wavelengths of 1584 nm and 1600 nm have been described and optimized, with an aim to achieve better pumping conditions for a Thulium (Tm)-doped fibre laser. Optimization of the system has been carried out involving the studies on the different lengths of the Er-...
The design and development of a new fibre optic sensor system for the optical detection of leakages in sewerage tunnels is reported. The system developed overcomes the disadvantages of the usually employed camera based inspection systems which are relatively complex and, in addition, require cleaning of the structures to be monitored beforehand. Th...
A pressure sensor (10 for medical applications comprises a silica optical fiber extrinsic Fabry-Perot interferometric (EFPI) pressure sensor (2) and an in-fiber Bragg grating (FBG, 3). The cavity of the EFPI pressure sensor (2) is formed by the end face of the FBG (3), a glass capillary (5) and a glass diaphragm (6). The glass diaphragm (6) is secu...
This paper presents the design of a sensor packaging for a Fibre Bragg Grating (FBG) based fibre optic humidity sensor. The evaluation of the developed fibre optic sensor was performed under experimental conditions and verified its capability to withstand highly alkaline environments. Therefore, the sensor can be applied to monitor the concrete hum...
In this paper a compact, yet sensitive gas detection system based on a modulated, tunable thulium-doped fiber laser in the 2 μm wavelength region is reported. The laser operating wavelength range centered at a wavelength of 1.995 μm has been selected to access the R(50) transition ( ν 1 + 2 ν 2 + ν 3 ) of CO 2 based on its line strength and to achi...
Recent research has shown that the transmission spectrum of a long period grating (LPG) written into an optical fiber is sensitive to the thickness and the refractive index (RI) of a thin layer deposited on it, a concept which forms the basis of a number of optical fiber sensors. The research reported herein is focused, in particular, on sensors of...
The sensitivity of a Long Period Grating (LPG)-based refractive index (RI) sensor has been enhanced through an
appropriate coating of a thin polymer layer, with a higher RI than that of the cladding, on the LPG. The performance of
the coated sensor, together with a bare LPG, was evaluated as a chemical sensor when the sodium chloride concentration...
A stable and tunable thulium-doped “all-fiber” laser offering a narrow linewidth has been created specifically to act as a compact and simple laser source for gaseous CO 2 detection. This has been done through a careful design to match the laser output wavelengths to the CO 2 absorption lines at 1.875 and 1.997 μm, respectively. A sustainable outpu...
An Optical fiber Pressure Sensor (OFPS also referred to as FOPS) is combined with an Optical fiber Bragg Grating (FBG) to create a pressure and temperature sensitive sensor in a single optical fiber. This sensor is novel in its design and fabrication and it is using quartz glass only. The novel design allows access to in-vivo biomedical pressure me...
To understand the behaviour of rocks under changing load or temperature
conditions, the determination of physical parameters like pore pressure or
temperature within the pore space is essential. Within this study, the
implementation of a novel fibre optic point sensor for pressure and temperature
determination into a high pressure / high temperatur...
This paper discusses a Single Wavelength Interroga- tion (SWI) technique used to measure fast changing pressure re- lated signals and over a large operational temperature range. The novel technique is based on a fiber-optic pressure and temperature hybrid sensor, and a feedback stabilization technique for a tunable laser source. The fiber-optic hyb...
In this paper the fabrication of a miniature all-glass fibre optic pressure and temperature sensor is presented. The sensor combines the functionality of a miniature all-silica diaphragm based Extrinsic Fabry Perot Interferometric (EFPI) Fibre Optic Pressure Sensor (FOPS) and an in-Fibre Bragg Grating (FBG) sensor. The reported fibre optic sensor h...
In this paper the low pressure response and resolution of a temperature compensated miniature all-glass Fibre Optic Pressure Sensor (FOPS) is evaluated. The active temperature compensation of a diaphragm based all-silica Extrinsic Fabry Perot Interferometric (EFPI) FOPS is established by encapsulating a Fibre Bragg Grating (FBG) within the EFPI cav...
Advancements in optical technology have led to the development of a number of different sensor systems suitable for use in the biomedical industry, such as cardiovascular system monitors, lung/bladder pressure sensors and radiation dosimeters. Recent efforts in the Optical Fibre Sensors Research Centre at the University of Limerick have seen the ap...
Sensing the pressure of gasses in the exhaust manifold of an internal combustion engine is a challenging application. The exhaust gasses themselves are rapidly changing with temperatures involved that can be in the region of 800°C. This paper presents a Fibre Optic Pressure Sensor (FOPS) system designed specifically for this application. The FOPS s...
In this paper a fibre optic sensor is developed and tested to measure pressure and temperature under simulated wellbore conditions. The sensor consists of a miniature all-silica fibre optic Extrinsic Fabry-Perot Interferometer (EFPI) sensor which has a novel embedded Fibre Bragg Grating (FBG) reference sensor element to determine both pressure and...
This paper proposes a novel technique to stabilise the output wavelength of a tuneable laser source to operate always in the linear range of a miniature all-silica Extrinsic Fabry-Perot Interferometric (EFPI) fibre optic pressure sensor. The technique is based on a fibre optic hybrid sensor, which consists of a miniature all-silica EFPI fibre optic...
A labial flue pipe is a well known tone generator, which is familiar and easily recognizable as the organ pipes seen in many concert halls and churches. However, the design and understanding of the sounding mechanism of such pipes are fraught with difficulty. Traditionally labial pipes are constructed from age-old lookup tables that are closely gua...
This paper presents a novel concept of simultaneously measuring pressure and temperature using a silica optical fibre extrinsic Fabry-Perot interferometric (EFPI) pressure sensor incorporating a fibre Bragg grating (FBG), which is constructed entirely from fused-silica. The novel device is used to simultaneously provide accurate pressure and temper...
A micro diaphragm-based Extrinsic Fabry-Perot Interferometric (EFPI) pressure sensor with high temperature immunity is described. The EFPI pressure sensor consists of a single mode silica glass optical fiber, a glass capillary and a glass diaphragm, which are fused together using a conventional fusion splicer. This eliminates the need for the use o...
Traditional temperature measurement devices such as bimetallic strips, thermocouples, RTDs, radiation devices (i.e. Infrared), silicon P-N junctions etc. all have limitations such as range or slow response times due to them having to dasiareachpsila temperature. These limitations, while normally not an issue become so where high speed operation or...
Citations
... Based on the unique features discussed above, we developed a single sensor element consisting of an etched OM4 GI-MMF and a BG to obtain simultaneous measurement of RI and temperature at the point of measurement [13,14]. The concept of the proposed fiber optic sensor-head is shown in Fig. 1(a). ...
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... FOS, as a well-established SHM technique, has also been applied in the field of composites [35]- [39]. Optical fibers, due to their small size, can be embedded in composites and used as sensing elements to measure a wide range of parameters including temperature, humidity, strain, and vibrations [40]- [47]. ...
... Thus, the deformed optical fibers affect the light transmission inside the cables, and different techniques of fiber-optic shape sensing can measure the change of curvature due to fiber deformation. Some of the typical methods for fiber-optic curvature detection are (i) fiber Bragg gratings [5][6][7][8], (ii) Brillouin optical time domain analysis (BOTDA) [9,10], (iii) Rayleigh scattering [11,12], (iv) the photonic crystal approach [13], and (v) Mach-Zehnder interferometer (MZI) [14][15][16][17][18][19]. The first three methods can be grouped as a category of backscattered light analysis, while the last two methods can be regarded as photonic techniques. ...
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... In the future, it can be expected that a measuring system will have a far-reaching influence on the physiological parameters to be recorded in the field [160,161]. The benefit of this development is that the results obtained in the laboratory can be reproduced within the scope of a field trial [162,163]. Thus, the simulation can advance, resulting in a more realistic depiction [164,165]. The presented solution approach (mobPhysioLab®) significantly improves the collection of field physiological data. ...
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... This enables to quantify bending in all three dimensions. The developed technology represents a promising approach for applications in medical diagnostics to detect motion of patients [29]- [31], in robotics and augmented reality scenarios including gaming gloves or motion-recording wearables for use in sports and motion capture [32], [33], to name a few. ...
... There is a steadily increasing demand for portable biosensors, hence also an immediate need for biosensor miniaturization [12]. Point-of-care biosensors can be divided into hand-held devices and benchtop devices, which are reduced forms of large laboratory equipment in terms of size and complexity [13][14][15][16]. Although ELISA is the gold standard for clinical diagnosis tests for many viral and bacterial diseases some problems with ELISA are the requirements of expensive instruments and skilled professionals as well as long waiting times to obtain the results. ...
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... The previous paragraph explains the SPR biosensor that uses a prism to implement it. Other coupling methods that can be used as alternatives include gratings [39,40], waveguide [41,42], and optical fiber [43,44]. The basic differences between these four coupling methods are shown in Figure 3. ...
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... Interrogating FBGs in multimode fibers, including POFs, is more complex compared with single-mode fibers (SMFs) due to the overlapping spectra from different modes [68]. Among the most common techniques used to overcome this limitation involves mode demultiplexing or the use of mode-division multiplexers (MDMs) [69]. Mode-demultiplexing involves employing specialized devices or algorithms to distinguish the responses from different modes. ...
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... There is a steadily increasing demand for portable biosensors, hence also an immediate need for biosensor miniaturization [12]. Point-of-care biosensors can be divided into hand-held devices and benchtop devices, which are reduced forms of large laboratory equipment in terms of size and complexity [13][14][15][16]. Although ELISA is the gold standard for clinical diagnosis tests for many viral and bacterial diseases some problems with ELISA are the requirements of expensive instruments and skilled professionals as well as long waiting times to obtain the results. ...
![[object Object]](https://i1.rgstatic.net/ii/profile.image/1089231086714883-1636704336882_Q64/Torsten-Schueling.jpg)
... FMF has been used extensively in communication applications to augment the transmission capacity and for selective mode couplers [22][23][24][25][26]. For example, an FMF-based mode-selective coupler was developed to achieve mode division multiplexing from 1515-1590 nm. ...
