Maria Beblowska

Optoelectronic capillary sensors in microfluidic and point-of-care instrumentation.

This paper presents a review, based on the published literature and on the authors’ own research, of the current state of the art of fiber-optic capillary sensors and related instrumentation as well as their applications, with special emphasis on point-of-care chemical and biochemical sensors, systematizing the various types of sensors from the point of view of the principles of their construction and operation. Unlike classical fiber-optic sensors which rely on changes in light propagation inside the fiber as affected by outside conditions, optical capillary sensors rely on changes of light transmission in capillaries filled with the analyzed liquid, which opens the possibility of interesting new applications, while raising specific issues relating to the construction, materials and instrumentation of those sensors.

A Method of Examination of Liquids by Neural Network Analysis of Reflectometric and Transmission Time Domain Data From Optical Capillaries and Fibers

This paper presents the construction and working principles of an intelligent fiber-optic sensor used for liquid examination using time domain data. The sensing elements consisted of a length of optical fiber or a short section of optical capillary and worked either on the reflection intensity basis or on transmission intensity basis. The changes of the monitored signal are caused mainly by the variation in light propagation conditions at the interfaces of liquid and gaseous phases and formation of drops of liquids or lenses at liquid-vapor interfaces. The physical effects on which depends the formation of a drop of liquid or a lens are surface tension, viscosity, boiling point, vapor pressure of liquid and its heat capacity. They provide information allowing determining the type of the liquid by a procedure which includes submerging, submersion, emerging and emergence of the sensing head from the examined liquid, or by local heating of the liquid sample. The measured data were analyzed using neural networks.

Short capillary tubing as fiber optic sensor of viscosity of liquids

Optical capillaries are used in capillary gas and liquid chromatography, capillary electrophoresis, absorbance spectroscopy, Raman spectroscopy etc. These micro-fluidic methods find applications in biotechnologies, medical diagnostic, drug discovery and environmental sciences. In the presented work we discuss some aspects of light guidance in capillary tubing made from silica glass or Teflon AF. The wide range of capillary constructions allows them to be used advantageously in specific applications. We have analyzed both theoretically and experimentally partially liquid filled optical capillaries as fiber optic sensor elements in laser light transmission and reflection conditions at 670, 1310 and 1550 nm. We have shown that the light transmission properties and signal in the reflectometric mode of work depend on capillary construction, their length and position of inserted liquid drop. The results obtained by us show that capillary tubing can be used as sensing elements in optical fiber sensors of surface tension and viscosity of small liquid samples with volume below 10-8 cm3.

Light transmission characteristics of silica capillaries

The paper discusses certain aspects of the light guidance in capillary tubing and the possibilities of its utilization in fibre optic sensors heads.

A method of examination of liquids by neural network analysis of reflectometric time domain data from optical capillaries and fibers

This paper presents the construction and working principles of a reflectometric intelligent fiber-optic sensor used for liquid examination. Unlike other well-known fiber optical sensors which use information from optical wavelength variations, the proposed system uses time domain data. The sensing element consists of a length of optical fiber and a short section of optical capillary and works on the reflection intensity basis. The reflected signal level depends on the optical construction of the sensor element. The changes of the monitored signal are caused mainly by variation in light propagation conditions at the interfaces of liquid and gaseous phases. The physical effects involved are Fresnel reflection, local numerical aperture variation and liquid lenses formation. It is possible to call out across the changes of those effects by introducing a measuring procedure which includes submerging, submersion, emerging and emergence of the sensing head from the examined liquid or by local heating of the liquid sample.

Plastic optical fibers in sensors: a review

Basic properties of thermoplastic optical fibers are described. Resulting possibilities and limitations of polymer fiber use in optical sensors are discussed. As an example the idea of the integrated alarm system head, containing smoke, temperature and humidity sensors, is shown.

Intelligent Photonic Sensors for Application in Decentralized Wastewater Systems

Michal Borecki1, Michael L. Korwin-Pawlowski2, Maria Beblowska1, Jan Szmidt1, Maciej Szmidt3, Mariusz Duk4, Kaja Urbanska3 and Andrzej Jakubowski1 1Institute of Microelectronics and Optoelectronics, Warsaw University of Technology, 2Departement d’informatique et d’ingenierie, Universite du Quebec en Outaouais, 3Warsaw University of Life Sciences, 4Lublin University of Technology, 1,3,4Poland 2Canada

Design and performance of the asymmetrical coupler of plastic optical fibers

Presented work concerns designing and making the asymmetric couplers. Three-dimensional fiber space modeling of light propagation have been used in the project. Couplers were made using two different technologies of gluing. Design results are confirmed by experiments and elements have expected parameters.

The proposition of reflectometric fibre optic load sensor

Fibre optic load sensor are gaining attention because of their immunity to electromagnetic and radio frequency interference, suitability for use at elevated temperatures, and intrinsically safe nature. Construction of load sensor for application in safety systems has been presented. The device consists of sensors head and source and detector units. Designed sensor could be mounted in monitored place (e.g. under a floor) and controlled by PC unit or could be used as a portable device for a valuable object protection.

Optimal model look for active optical fibers in amplifier applications

This work presents the idea of the conversion of the optoelectronic system into the functional electric model on the example of fiber amplifier. The functional model is formulated in a long line of lumped constants form. It is dedicated for electrical simulators like SPICE (Simulation Program for Integrated Circuit Emphasis). It can be widely used in design and analysis of fiber transmission lines, whose optical fiber amplifier is one of the most important parts. This model together with previous showed analysis enables qualification time life of ions in excited state in working amplifier.