Hardy Baierl - Academia.edu (original) (raw)
Papers by Hardy Baierl
The proceedings of the JSME annual meeting, 2006
2014 Third Mediterranean Photonics Conference, 2014
A segment of a suspended-core microstructured fibre was dipped in a droplet of acetone and the ev... more A segment of a suspended-core microstructured fibre was dipped in a droplet of acetone and the evaporation dynamics of remaining acetone inside the cavity were simultaneously analysed with an optical microscope and an optical spectrum analyser. When the fibre is immersed it suffers a 14 dB signal drop. Different menisci form in each cladding cavity, with different evaporation times and rates. The signal restores its initial state not when the evaporation process is complete but after the collapse of a dominant meniscus.
Optics letters, 2014
A sensing configuration for fluid evaporation monitoring using a suspended-core fiber tip is prop... more A sensing configuration for fluid evaporation monitoring using a suspended-core fiber tip is proposed. Strong differences between the evaporation processes of acetone and isopropyl alcohol were observed, both in terms of the signal's intensity fluctuations and total duration. In each fluid, the main signal variations were due to changes in reflectivity inside a collapsed region of the suspended-core fiber near the spliced interface with a standard single-mode fiber. After further analysis with a wider array of substances, this configuration could, in the future, be used to detect and study the evaporation of different volatile organic compounds.
SPIE Proceedings, 2014
In this work, an all-fiber loop mirror using a four-bridge silica fiber with a double-Y-shaped su... more In this work, an all-fiber loop mirror using a four-bridge silica fiber with a double-Y-shaped suspended-core is presented for the measurement of strain and torsion. The sensing head is formed by a section of the microstructured fiber with 90 mm in length. The fiber loop sensor allowed observing a distinct interference pattern as a result of the geometry of the core fiber. Different sensitivities to strain and torsion were obtained, namely,-5.11 pm/με and ±1.34 pm/degree.
23rd International Conference on Optical Fibre Sensors, 2014
ABSTRACT In this work, a hybrid Fabry-Perot interferometer based on a novel four-bridge microstru... more ABSTRACT In this work, a hybrid Fabry-Perot interferometer based on a novel four-bridge microstructured fiber is presented and characterized. The characterization of this cavity is performed in the L-band using two different instruments: an optical spectrum analyzer and an optical backscatter reflectometer. The Fabry-Perot output signal presents linear variation with temperature changes (sensitivity 9.8-11.9 pm/ºC), variation with the polarization states of light and high stability.
23rd International Conference on Optical Fibre Sensors, 2014
Plasma Processes and Polymers, 2020
In this paper we will discuss the influence of atmosphere pressure microwave plasma on the backgr... more In this paper we will discuss the influence of atmosphere pressure microwave plasma on the background loss and the radial distribution of several dopants in specialty, especially rare-earth (RE) doped, preforms and fibers for high power application. In conclusion we were able to demonstrate a significant improvement in the homogeneity of the distribution of the codopants within the silica matrix. Furthermore, we used the plasma process for the functionalization of pure and doped particles as basic raw material in the powder-based reactive powder sintering of silica (REPUSIL) process. In further experiments we will use plasma technology for the all-in-one doping of both active and passive dopants for a brightness adjustment of the refractive index of specialty fibers.
Journal of Physics D: Applied Physics, 2018
The world has faced three Information and Communication Technology (ICT) revolutions and the thir... more The world has faced three Information and Communication Technology (ICT) revolutions and the third ICT wave led to Internet of Things, the notion of anything, everything, anytime and everywhere. Out of the many visions of IoT, one revolutionary concept is to make IoT sociable i.e., incorporating social networking within Internet of Things. This revolution has led to the notion of Social Internet of Things (SIoT). Establishing a SIoT network or community is not so simple and requires integration of heterogeneous technology and communication solutions. This paper focuses on establishing a secure and reliable communication over nodes in SIoT by computing trust dynamically among neighboring nodes. Trust Management is an important area that has attracted numerous researchers over the past few years. The proposed DTrustInfer computes trust based on first hand observation, second hand observation, centrality and dependability factor of a node. Properties of trust such as honesty, cooperativeness, community interest and energy of a node are considered for computing trust. Also, this paper ensures secure communication among SIoT nodes through simple secret codes. Experimental results show that the proposed DTrustInfer outperforms the existing trust models significantly.
Sensors (Basel, Switzerland), Jan 7, 2015
A hybrid Fabry-Pérot cavity sensing head based on a four-bridge microstructured fiber is characte... more A hybrid Fabry-Pérot cavity sensing head based on a four-bridge microstructured fiber is characterized for temperature sensing. The characterization of this cavity is performed numerically and experimentally in the L-band. The sensing head output signal presents a linear variation with temperature changes, showing a sensitivity of 12.5 pm/°C. Moreover, this Fabry-Pérot cavity exhibits good sensitivity to polarization changes and high stability over time.
This paper presents an innovative one-step doping approach for the preparation of Al-Yb co-doped ... more This paper presents an innovative one-step doping approach for the preparation of Al-Yb co-doped silica glasses for fiber preforms. Today, fiber-lasers are of great interest in industry due to highest precision and flexibility in system design combined with high power output and excellent beam quality. Industrially established processes such as modified chemical vapor deposition (MCVD), outside vapor deposition (OVD) and reactive powder sintering technology (REPUSIL) are used to fabricate co-doped silica glasses for laser fibers. However, none of these processes is able to simultaneously incorporate laser active dopants increasing the refractive index (rare earth elements, RE), glass matrix modifiers (e.g. aluminum, Al2O3) and dopants reducing the refractive index (e.g. fluorine, F). Instead, the incorporation of the individual refractive index changing dopants, into a silica glass matrix, has to be carried out in subsequent and separate steps. The novel approach pursues to overcome...
The invention relates to a particulate material, a process for its preparation and the use of the... more The invention relates to a particulate material, a process for its preparation and the use of the particulate material. As a usable for the production of high-quality optical component material a single-phase particulate material is formed of at least two oxides of elements selected from a group comprising metals, semi-metals and phosphorus indicated. The preparation of such a material is performed by plasma treatment using a plasma-forming gas is introduced into a reaction chamber and are there ionized so that a plasma is formed, a raw material in the region of the plasma is initiated, treating the starting material under the action of the plasma and the material formed is removed from the region of the plasma, wherein the plasma is performed such that the starting material undergoes such a residence time in the plasma that forms a single phase particulate material.
Coal has been for centuries a central energy source to fulfill industrial and domestic needs. Its... more Coal has been for centuries a central energy source to fulfill industrial and domestic needs. Its large scale extraction produced huge amount of debris that were piled in the neighboring of the mines, quite often going into combustion triggered by events like forest fires or lightning. When in this state it can continue for years, releasing substantial emissions of toxic and greenhouse gases with recognized impact in the environment and, more serious in the short term, in the life quality of the populations located nearby. Continuous monitoring of combustion temperature and emission levels of certain gases opens the possibility to plan corrective actions to minimize their negative impact. Optical fiber technology is well-suited to this purpose and here it is described the main attributes of a fiber optic sensing system projected to gather data on distributed temperature and gas emission in these harsh environments.
Journal of Physics D: Applied Physics
Plasma Physics and Technology Journal, Nov 29, 2019
A plasma source based on a microwave discharge at atmospheric pressure is used to produce an oxyg... more A plasma source based on a microwave discharge at atmospheric pressure is used to produce an oxygen plasma torch. A liquid precursor material is evaporated and injected into the torch through a nozzle, causing oxidization and deposition of silica at a nearby quartz substrate. The temperature generated inside the plasma source and in the plume, in the region of treatment, and at the substrate surface are key parameters, which are needed for process description and optimization of plasma-chemical reactions. Optical emission spectroscopy and thermography were applied to observe and characterize the jet behavior and composition. The experimental results are compared with self-consistent modeling.
Applied Sciences
The combustion of coal wastes resulting from mining is of particular environmental concern, and t... more The combustion of coal wastes resulting from mining is of particular environmental concern, and the importance of proper management involving real-time assessment of their status and identification of probable evolution scenarios is recognized. Continuous monitoring of the combustion temperature and emission levels of certain gases allows for the possibility of planning corrective actions to minimize their negative impact on the surroundings. Optical fiber technology is well suited to this purpose and here we describe the main attributes and results obtained from a fiber optic sensing system projected to gather data on distributed temperature and gas emissions in these harsh environments.
The proceedings of the JSME annual meeting, 2006
2014 Third Mediterranean Photonics Conference, 2014
A segment of a suspended-core microstructured fibre was dipped in a droplet of acetone and the ev... more A segment of a suspended-core microstructured fibre was dipped in a droplet of acetone and the evaporation dynamics of remaining acetone inside the cavity were simultaneously analysed with an optical microscope and an optical spectrum analyser. When the fibre is immersed it suffers a 14 dB signal drop. Different menisci form in each cladding cavity, with different evaporation times and rates. The signal restores its initial state not when the evaporation process is complete but after the collapse of a dominant meniscus.
Optics letters, 2014
A sensing configuration for fluid evaporation monitoring using a suspended-core fiber tip is prop... more A sensing configuration for fluid evaporation monitoring using a suspended-core fiber tip is proposed. Strong differences between the evaporation processes of acetone and isopropyl alcohol were observed, both in terms of the signal's intensity fluctuations and total duration. In each fluid, the main signal variations were due to changes in reflectivity inside a collapsed region of the suspended-core fiber near the spliced interface with a standard single-mode fiber. After further analysis with a wider array of substances, this configuration could, in the future, be used to detect and study the evaporation of different volatile organic compounds.
SPIE Proceedings, 2014
In this work, an all-fiber loop mirror using a four-bridge silica fiber with a double-Y-shaped su... more In this work, an all-fiber loop mirror using a four-bridge silica fiber with a double-Y-shaped suspended-core is presented for the measurement of strain and torsion. The sensing head is formed by a section of the microstructured fiber with 90 mm in length. The fiber loop sensor allowed observing a distinct interference pattern as a result of the geometry of the core fiber. Different sensitivities to strain and torsion were obtained, namely,-5.11 pm/με and ±1.34 pm/degree.
23rd International Conference on Optical Fibre Sensors, 2014
ABSTRACT In this work, a hybrid Fabry-Perot interferometer based on a novel four-bridge microstru... more ABSTRACT In this work, a hybrid Fabry-Perot interferometer based on a novel four-bridge microstructured fiber is presented and characterized. The characterization of this cavity is performed in the L-band using two different instruments: an optical spectrum analyzer and an optical backscatter reflectometer. The Fabry-Perot output signal presents linear variation with temperature changes (sensitivity 9.8-11.9 pm/ºC), variation with the polarization states of light and high stability.
23rd International Conference on Optical Fibre Sensors, 2014
Plasma Processes and Polymers, 2020
In this paper we will discuss the influence of atmosphere pressure microwave plasma on the backgr... more In this paper we will discuss the influence of atmosphere pressure microwave plasma on the background loss and the radial distribution of several dopants in specialty, especially rare-earth (RE) doped, preforms and fibers for high power application. In conclusion we were able to demonstrate a significant improvement in the homogeneity of the distribution of the codopants within the silica matrix. Furthermore, we used the plasma process for the functionalization of pure and doped particles as basic raw material in the powder-based reactive powder sintering of silica (REPUSIL) process. In further experiments we will use plasma technology for the all-in-one doping of both active and passive dopants for a brightness adjustment of the refractive index of specialty fibers.
Journal of Physics D: Applied Physics, 2018
The world has faced three Information and Communication Technology (ICT) revolutions and the thir... more The world has faced three Information and Communication Technology (ICT) revolutions and the third ICT wave led to Internet of Things, the notion of anything, everything, anytime and everywhere. Out of the many visions of IoT, one revolutionary concept is to make IoT sociable i.e., incorporating social networking within Internet of Things. This revolution has led to the notion of Social Internet of Things (SIoT). Establishing a SIoT network or community is not so simple and requires integration of heterogeneous technology and communication solutions. This paper focuses on establishing a secure and reliable communication over nodes in SIoT by computing trust dynamically among neighboring nodes. Trust Management is an important area that has attracted numerous researchers over the past few years. The proposed DTrustInfer computes trust based on first hand observation, second hand observation, centrality and dependability factor of a node. Properties of trust such as honesty, cooperativeness, community interest and energy of a node are considered for computing trust. Also, this paper ensures secure communication among SIoT nodes through simple secret codes. Experimental results show that the proposed DTrustInfer outperforms the existing trust models significantly.
Sensors (Basel, Switzerland), Jan 7, 2015
A hybrid Fabry-Pérot cavity sensing head based on a four-bridge microstructured fiber is characte... more A hybrid Fabry-Pérot cavity sensing head based on a four-bridge microstructured fiber is characterized for temperature sensing. The characterization of this cavity is performed numerically and experimentally in the L-band. The sensing head output signal presents a linear variation with temperature changes, showing a sensitivity of 12.5 pm/°C. Moreover, this Fabry-Pérot cavity exhibits good sensitivity to polarization changes and high stability over time.
This paper presents an innovative one-step doping approach for the preparation of Al-Yb co-doped ... more This paper presents an innovative one-step doping approach for the preparation of Al-Yb co-doped silica glasses for fiber preforms. Today, fiber-lasers are of great interest in industry due to highest precision and flexibility in system design combined with high power output and excellent beam quality. Industrially established processes such as modified chemical vapor deposition (MCVD), outside vapor deposition (OVD) and reactive powder sintering technology (REPUSIL) are used to fabricate co-doped silica glasses for laser fibers. However, none of these processes is able to simultaneously incorporate laser active dopants increasing the refractive index (rare earth elements, RE), glass matrix modifiers (e.g. aluminum, Al2O3) and dopants reducing the refractive index (e.g. fluorine, F). Instead, the incorporation of the individual refractive index changing dopants, into a silica glass matrix, has to be carried out in subsequent and separate steps. The novel approach pursues to overcome...
The invention relates to a particulate material, a process for its preparation and the use of the... more The invention relates to a particulate material, a process for its preparation and the use of the particulate material. As a usable for the production of high-quality optical component material a single-phase particulate material is formed of at least two oxides of elements selected from a group comprising metals, semi-metals and phosphorus indicated. The preparation of such a material is performed by plasma treatment using a plasma-forming gas is introduced into a reaction chamber and are there ionized so that a plasma is formed, a raw material in the region of the plasma is initiated, treating the starting material under the action of the plasma and the material formed is removed from the region of the plasma, wherein the plasma is performed such that the starting material undergoes such a residence time in the plasma that forms a single phase particulate material.
Coal has been for centuries a central energy source to fulfill industrial and domestic needs. Its... more Coal has been for centuries a central energy source to fulfill industrial and domestic needs. Its large scale extraction produced huge amount of debris that were piled in the neighboring of the mines, quite often going into combustion triggered by events like forest fires or lightning. When in this state it can continue for years, releasing substantial emissions of toxic and greenhouse gases with recognized impact in the environment and, more serious in the short term, in the life quality of the populations located nearby. Continuous monitoring of combustion temperature and emission levels of certain gases opens the possibility to plan corrective actions to minimize their negative impact. Optical fiber technology is well-suited to this purpose and here it is described the main attributes of a fiber optic sensing system projected to gather data on distributed temperature and gas emission in these harsh environments.
Journal of Physics D: Applied Physics
Plasma Physics and Technology Journal, Nov 29, 2019
A plasma source based on a microwave discharge at atmospheric pressure is used to produce an oxyg... more A plasma source based on a microwave discharge at atmospheric pressure is used to produce an oxygen plasma torch. A liquid precursor material is evaporated and injected into the torch through a nozzle, causing oxidization and deposition of silica at a nearby quartz substrate. The temperature generated inside the plasma source and in the plume, in the region of treatment, and at the substrate surface are key parameters, which are needed for process description and optimization of plasma-chemical reactions. Optical emission spectroscopy and thermography were applied to observe and characterize the jet behavior and composition. The experimental results are compared with self-consistent modeling.
Applied Sciences
The combustion of coal wastes resulting from mining is of particular environmental concern, and t... more The combustion of coal wastes resulting from mining is of particular environmental concern, and the importance of proper management involving real-time assessment of their status and identification of probable evolution scenarios is recognized. Continuous monitoring of the combustion temperature and emission levels of certain gases allows for the possibility of planning corrective actions to minimize their negative impact on the surroundings. Optical fiber technology is well suited to this purpose and here we describe the main attributes and results obtained from a fiber optic sensing system projected to gather data on distributed temperature and gas emissions in these harsh environments.