The accurate measurement of temperature changes is the key skill not only for predictions of various natural phenomena or to detect intrusion of the object. The temperature changes we nowadays measure in local climate zones or Urban Heat Islands. The environmental quality is an essential feature of life quality and to improve it serve many remote sensing-based urban planning indicators, which are the common part of present smart cities.
Continuously developing fibre optic sensors allow their benefits to be exploited in more and more applications. Defensive Perimeter Detection by Polarization Change of the Fiber Optic Signal offers an effective possibility to detect quickly and in time disturbing a predefined space. This detection system uses the polarizing properties of light and, in particular, the birefringence of optical fibres. The disclosed detection system focuses on temperature changes that may be caused by external or internal disruption of the site. The main detection equipment is the polarization maintaining optical fibre with the same excitation in both polarization axes. The transmission rate in both axes is in the ideal case the same, but due to birefringence, inhomogeneity, and imperfection of production and next causes the mutual delay of both signals causes the signal polarization state change or even the series of polarization states changes, which can be observed in laboratory conditions and described by known mathematical methods. However, these changes can be transformed by linear polarizer to the intensity changes. This conversion allows the changes significantly easier to evaluate.
The paper deals with the analytical description of the sensitivity and dynamic characteristics of the birefringent fiber temperature response usable for realization of thermal field disturbance sensors. The response is given by changing the phase shift development between two polarization modes in birefringent fiber, caused by body heat transfer of different temperatures. The aim is to analyze sensitivity and dynamic behaviors, which are significant when optical fiber is used as a sensor of temperature field disturbance. The result shows a very good match with measured time responses, especially due to a specific arrangement for suppressing the influence of conduction and convection.
Due to increasing demands for bandwidth are nowadays very popular optical networks. Installation of new fiber-optic networks is expensive, so is necessary to use existing fiber optic network very effectively. The main parameters that limit the optical networks are dispersion and attenuation. Efficiency optical networks could improve the use of two polarization axes, similar to the technology used in radio technologies. Use of fiber preserves polarization allows the use of two polarization planes. This article deals with the optical wavelength division multiplex in the polarization maintaining fibers.
This paper continues previous research work dealing with the study of sensor of thermal field disturbance. The
utilization of polarization maintaining fiber (PMF) birefringence high sensitivity upon the temperature is taken in
advantage. The effect of laser source wavelength and optical fiber beat length upon the fiber response invoked by
disturbing temperature field is theoretically analyzed. The sensitivity of optical fiber response upon the temperature
disturbing is experimentally verified. The optical fibers for wavelength 633 nm and 1550 nm with its beat length 2 mm
and 5 mm are used in experiment. The experimental work was conducted for different lengths of disturbing temperature
radiation sources from fiber-optic sensor and for different length of sensor exposed to the radiation. The relation of fiber
response for the wavelength of 633 nm upon different magnitude of disturbing temperature radiation was also
investigated. The particular results of experimental work are presented in this paper. The construction of sensor system
with desired sensitivity and selection of its parameters can be done based on the obtained results.
Paper presents some results obtained by the measurement of polarization properties of fibers in the incidence of different external effects as temperature, torsion and magnetic field. To emphasize applied physical effect rare earth (Nd3+) fiber has been used. Study of polarization is important from the polarization dispersion point of view for communication systems and also in the area of interferometric and polarization sensors, distributed sensors or general interferometric measurements. Analysis of individual effects is solved theoretically and practically in the series of works. Our contribution solves a relatively short part of fiber, where additionally fluctuation of power between both polarization modes could affect.
A new software package, suitable for performing polarization analysis in optical networks is presented. The user can input any initial state of polarization using Jones and Stokes vectors, the polarization ellipse and the density matrix. Each device and optical network can be defined using Jones and Muller matrices, and the quaternions, which represents the device in terms of the four Pauli matrices. The final state of polarization is calculated, and presented using the methods mentioned above, as well as the graphical representation of the polarization ellipse and the Poincare sphere. The extension to first-order component defects in general ellipsometry is included. It can be used for educational and research purposes.
Except of specialists, dealing with different photonics areas, the education of all technical professionals about basic photonics principles, components, applications and system solutions is necessary. Paper deals with the place of photonics in the basic range of education and also in other facultative subjects developing the basic photonics knowledge to the area of systems solution. Photonics education is carried in the three steps: in electrical engineering subjects, in the facultative subjects and in the professional subjects. Basic professional spheres of electrical engineering student education could be as follows: theory of field, theory of signals, theory of information, electronic signals and systems, and electronic measurements. In Electrical Engineering and Electronics Department we offer two facultative subjects for different professions: Opto-electronics, and Fiber Optics. Both subjects are based on the lectures and also on the laboratory practice.
The aim of this paper is contribution to understanding of coupling between the polarization modes on the resultant transfer properties of single mode fiber given by the Jones matrix. In the case of ideal fiber it is possible to describe a propagation of the polarized optical wave by the Jones matrix and corresponding polarization eigenmodes with different propagation described by the Jones matrix are given not by the eigenmodes but by the principal states of polarization. Defined disturbance by the Jones matrix are given not by the eigenmodes but by the principal states of polarization. Defined disturbance along the whole fiber and also relatively defined variable coupling between the polarization modes it is possible to obtain by the torsion of fiber. Experimental evaluation of torsion effect by the Jones matrix elements can define the boundaries of application theory of polarization eigenmodes and principal states of polarization. These results can also contribute to understanding of conditions for polarization preserving of fiber and the development of polarization dispersion during disturbance of propagation conditions. Jones matrix elements have been measured on the working place published before and calculation and optimization of result are done by the use of software made for this purpose with the application of quaternions.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.