Jakub Jaros

Detection and localization of building insulation faults using optical-fiber DTS system

Nowadays the trends in the construction industry are changing at an incredible speed. The new technologies are still emerging on the market. Sphere of building insulation is not an exception as well. One of the major problems in building insulation is usually its failure, whether caused by unwanted mechanical intervention or improper installation. The localization of these faults is quite difficult, often impossible without large intervention into the construction. As a proper solution for this problem might be utilization of Optical-Fiber DTS system based on stimulated Raman scattering. Used DTS system is primary designed for continuous measurement of the temperature along the optical fiber. This system is using standard optical fiber as a sensor, which brings several advantages in its application. First, the optical fiber is relatively inexpensive, which allows to cover a quite large area for a small cost. The other main advantages of the optical fiber are electromagnetic resistance, small size, safety operation in inflammable or explosive area, easy installation, etc. This article is dealing with the detection and localization of building insulation faults using mentioned system.

Long-Term Polarization Mode Dispersion Evolution and Accelerated Aging in Old Optical Cables

Today’s optical networks are composed of thousands of kilometers of aging optical cables. Many of these cables are located in harsh environments, which contribute to induced birefringence of the fibers and a corresponding increase of polarization mode dispersion (PMD). This letter introduces derived statistics from the longest-known running evaluation of a PMD measuring campaign and an investigation into how higher optical power affects these aging systems. Results indicate strong seasonal dependence of PMD on temperature for an optical cable test bed exposed to atmospheric changes, leading to a 16% increase of a mean PMD value in summer. This fluctuation causes bit error rate limits to be exceeded for 10 and 40 Gbps non-return-to-zero signals, which is a critical issue for applications where high reliability is required. Moreover, due to the high optical power load within old optical infrastructures, a more than 0.15 dB increase of relative loss per year in tested routes, compared with reference routes, has been observed.

Study of LED modulation effect on the photometric quantities and beam homogeneity of automotive lighting

This paper discusses the implementation of a light emitting diode based visible light communication system for optical vehicle-to-vehicle (V2V) communications in road safety applications. The widespread use of LEDs as light sources has reached into automotive fields. For example, LEDs are used for taillights, daytime running lights, brake lights, headlights, and traffic signals. Future in the optical vehicle-to-vehicle (V2V) communications will be based on an optical wireless communication technology that using LED transmitter and a camera receiver (OCI; optical communication image sensor). Utilization of optical V2V communication systems in automotive industry naturally brings a lot of problems. Among them belongs necessity of circuit implementation into the current concepts of electronic LED lights control that allows LED modulation. These circuits are quite complicated especially in case of luxury cars. Other problem is correct design of modulation circuits so that final vehicle lightning using optical vehicle-to-vehicle (V2V) communication meets standard requirements on Photometric Quantities and Beam Homogeneity. Authors of this article performed research on optical vehicle-to-vehicle (V2V) communication possibilities of headlight (Jaguar) and taillight (Skoda) in terms of modulation circuits (M-PSK, M-QAM) implementation into the lamp concepts and final fulfilment of mandatory standards on Photometric Quantities and Beam Homogeneity.

The influence of temperature loading on the optical fiber passive components

The paper discuss about aging of the optical couplers in their burdened high temperature. The article focuses on applied research and experimental development of resources for safety operation of optical networks in environment with higher temperature. It addresses issues of accelerated aging of optical fiber components in their burdened with high temperature. This article is devoted the impact of temperature loading on the SM optical FBT coupler with 8 branches. Optical passive component were exposed to temperature 95 °C for 433 hours. Measurements are focused on the parameters of geometry of optical beam. The detect changes are useful to understand the phenomenon of accelerated ageing elements of optical networks.

Various optical fibers fixing methods for mechanical stress measurements

The monitoring of building structures deformations and testing of construction materials resilience are very important processes in the development and production of given materials and structures. This paper deals with the concrete deflection measurement using fiber optic distributed strain system. The own principle of the measurement evaluation is based on stimulated Brillouin scattering. In this paper, we explore the use of different types of optical fibers and the possibilities of their fixing. Above all, we are focusing on the possibility of their attachment to the measured objects. This is the most important step of the whole process that most affects the functionality and accuracy of measurement.

Impact of fixing materials on the frequency range and sensitivity of the fiber-optic interferometer

Fiber-optic sensors are one of the dynamically developing areas of photonics, which is today one of the key technologies. Here include even fiber optic interferometers, allowing very sensitive sensing, they are immune to electromagnetic interference and are entirely passive regarding electric power supply. This type of sensor is dependent on the phase shift, the principle of the function based on interference of light. Fiber optic interferometers are used especially in areas that require high sensitivity and measurement accuracy. The fundamental problem of fiber optic interferometry is a proposal storing and fixing the measuring arm of the interferometer and its influence on the frequency range and sensitivity of the interferometer. The authors focused on this issue and analyzed different types of fixing materials. We used a total of 8 different fixation elements with the different composition. We defined the standardized method of fixation and compared it with a reference measurement without fixation. For the analysis of the frequency characteristic of the prototype was used generator harmonic signal with fixed amplitude signal. Sensitivity verified using the size of the amplitude response. The signal processed by the application written in LabView development environment. The results clearly showed that it is necessary to pay attention to fixation materials in the design of the measuring arm of the interferometer for use in practical applications. In the frequency range, thanks to the fixing material increased the value of bandwidth about value 2430Hz against the reference measurements. The sensitivity of the interferometer has increased threefold. The results verified by retesting assembled prototype.

Masonry moisture measurement using the distributed temperature sensing system

Distributed temperature sensing systems (DTS) are based on the principle of time-domain reflectometry where an optical fiber acts as a temperature sensor. DTS is capable of measuring the temperature along the optical fiber using the nonlinear phenomenon referred as Raman scattering. The biggest advantage of such sensing system is the use of an optical fiber itself as a sensor which gives the benefits of electromagnetic interference immunity, low sensor cost, measurement distances up to 10 kilometers and the safe use in flammable and corrosive environments. Fiber optic DTS can be therefore used in the environments and processes in which the application of conventional sensors is impossible. This article discusses the use of DTS for the moisture measurement in the masonry. In structures with built-in optical fiber, the immediate detection and location of moisture are possible. To perform the measurements an experimental brick wall has been built and between each wall layer the optical fiber was placed. The wall was built in stainless steel tub with a drain valve and was placed on a mobile trolley. The dimensions of the wall were 106 x 100 x 30 cm. The actual measurements were carried out in two stages. In the first, the tub was filled with water and the temperature change associated with the gradual increase of moisture inside the wall was measured. This measurement lasted until the saturation which was the time when the wall has no more moisture to adopt. The second stage then examined the evolution of the temperature inside the wall during gradual desiccation until the time when the temperature inside the wall was uniform between all layers.

Analysis of the impact of the deposition optical fibers on the deformation measurement with a distributed system BOTDR

Authors of this article analyzed the influence of the cover layer in combination with the fixation material to measure deformation with the distributed system Brillouin Optical Time Domain Reflectometry (BOTDR). This system is based on the principle of measuring stimulated Brillouin scattering, which is frequency dependent on the measured temperature and the mechanical stress of the optical fiber. Standard telecommunication optical fiber G.652.D was used for experiments to verify whether this widely used type of fibers initially intended for telecommunication transmissions is suitable for measuring the deformation with the distributed system BOTDR. Knowing the impact of encapsulation type optical fiber is important in the use and implementation in practical applications. The results clearly show that it is important to pay attention to the implementation type of optical fiber. Based on post-analysis, it was determined the most appropriate implementation of optical fiber for optimal sensitivity in practical applications.

The behavior of the geometrical parameters of optical beam of optical passive components under the long time thermal load

TThe paper discuss about aging of the passive optical couplers in their burdened high temperature. The article focuses on applied research and experimental development of resources for safety operation of optical networks in environment with higher temperature. It addresses issues of accelerated aging of optical fiber components in their burdened with high temperature. How does temperature influence on optical network elements? It is necessary to specify the changes in the optical coupler and find out why these changes occur. This article is devoted experimental measurement of the impact of temperature loading on the geometrical parameters of optical beam of SM optical FBT couplers. In the paper there are compared couplers of different manufacturers and same dividing ratios of output power 1:8. Optical passive component were continuously exposed to temperature 95°C for long time period. Measurements are focused on the parameters of geometry of optical beam. Graphical and mathematical detect changes in the dissemination of energy coupler after long lasting dose of temperature loading are useful to understand the phenomenon of accelerated aging elements of optical networks in environments with an higher temperature.

Monitoring of the structural loads of tunnels using a distributed optical system BOTDR

Authors of this article focused on the analysis of the use of distributed fiber-optic technology for security monitoring of structural loads of road and motorway tunnels. Authors focused on measurements of deformation utilizing Brillouin Time Domain Reflectometry (BOTDR). The principle is based on the measurement of the stimulated Brillouin scattering. The article describes the load of tunnel based on the real measurements made during the construction of the motorway tunnel in the Slovakia Republic in a time horizon of several months. Experiments were carried out with standard optical telecommunication cable with water-absorbing aramid yarns and jacketing of diameter 4.2 mm. The outcome of this article is an introductory analysis the use of fiber-optic technology for security monitoring of structural loads for road and motorway tunnels.