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(J2-8192) Fluidni in mikro-fluidni optični-vlakenski senzorji (Slovene)


Measurements of physical and chemical properties of fluids are essential for variety of industrial and other sectors. Contemporary production systems heavily depend on modern process automation, which is impossible without substantial use of sensors and measurement systems. Branches of process industry, food processing industry, pharmaceutical industry, energy sector (oil&gas), biomedicine, environmental control & pollution monitoring are just few examples of sectors that are in strong demand for fluid parameter sensing. Besides traditional process industries, there are also new and emerging fields of fluidic technology, for example microfluidics, which set new demands on fluidic sensors in terms of size and their performance. Research and development of sensors for measurements of different fluid parameters is thus topic of intense research and development in both academia [see ref. in the section 12: 3-6, 11-17, 22, 23, 29, 31-34] and industry [see ref. in the section 12: 1, 2, 7-10, 18-21, 24-28, 30]. Many types of sensors for measurements of fluidic parameters are known in the art, but these solutions are mostly based on mechanical and electrical platforms, which have typical limitations like restricted temperature range, large size, limited compatibility with explosion hazards, they are difficult to operate over long distances or in remote locations, limited chemical compatibility, EMI and radio frequency interference sensitivity.

Optical methods have been proven as effective tools for characterization of fluids and measurements of fluid-mechanical parameters. Many of optical measurement methods exist in a form of commercial measurement solutions for off-line (mainly laboratory) monitoring or control. Optical sensors for on-line measurements and control are, however currently available for measurements of limited number of fluidic parameters. The most frequent optical sensors for on-line process control are those sensors based on optical spectroscopy [see ref. in the section 12: 25], refractive index (RI) [1] and for pressure [2] sensing. Emerging requirements within process industry and recent development of photonics technologies however drive further and significant penetration of optical measurement methods into other fluidic measurement technologies [see ref. in the section 12: 2]. This is due to the numerous advantages that can be offered by optical sensing technologies. For example, optical sensing technologies can provide different sensor-fluid interaction mechanisms, not available with other methods. These mechanisms might lead to new methods for fluid’s physical and chemical parameter sensing. However, these fluid-light interaction mechanisms, which draw initial use of optical methods in the process industry, are not the only drivers for introduction of optical technologies into fluidic sensing. Merger of optical sensing with fiber-optic technology can lead to a new class of fiber-optic sensors (FOS) for fluid sensing applications with a unique set of properties, not available with other sensing technologies. FOS are usually created at the tip or along of a silica optical fiber and are operated entirely through length of such a fiber. This guarantees fully dielectric and electrically passive interconnection between sensors and a control unit. Thus, by their nature, FOS provides high intrinsic explosion safety, chemical inertness of the sensor and interconnection line, electromagnetic interference immunity and broad operating temperature range. All these properties are essential for on-line measurements in process industry. The very same properties also make fiber-optic fluidic sensor ideal for use in in-vivo medical systems where patient safety and compatibility with sterilization process present a primary concern. Fiber sensors can be also operated over long distances in harsh environments, such as encountered in energy production sector. Furthermore, small/micro dimensions are natural to FOS, which makes FOS interesting candidates for microfluidic, biomedical, micro-reactor and similar applications that involve constrained spaces or small liquid volume sample analysis. All silica-glass design of FOS can also provide good bio-compatibility.

Recently, FOS have been successfully introduced into specialized industrial fields including civil structure monitoring, oil and gas sector, certain areas of biomedicine, aerospace and similar demanding sensing sectors. Fiber sensor technology has thus been proven as practical and useful sensing technology. Just recently FOS becomes an industry with a multibillion dollar revenues and this growth is expected to steadily continue throughout next decade (for example New ElectronicCast Consultants’ report issued in 2014 predicts 18 % yearly growth of global FOS market, rising from $1.89 billion in 2013 to $4.33 in 2018).

In spite of these recent research and commercial developments, FOS’s potential have been widely explored only for a sensing of very limited number of fluidic parameters. Among well-explored fluidic sensors are for example RI sensors [see ref. in the section 12: 22, 23] and fluid pressure sensors [3] (the latter are successfully commercialized by several business entities). Sensing of many other fluidic parameters, using fiber-optic sensing approach, remains in spite of their excellent application potential under-explored or explored in a very limited way. 

The main objective of the proposed project is to investigate, propose and demonstrate new types of FOS for measurement and detection of fluidic parameters. The proposed project shall in particular focus on following FOS:

a)           Micro-fiber-optic flow sensors

b)           Fiber optic fluid-level sensors

c)           Fiber-optic microcells for absorption and fluorescence spectroscopy

d)           Fiber-optic sensors for binary gas mixtures detection through sensing of refractive index with very high resolution

e)           Fiber-optic sensors for sensing of physical fluid properties, which are hard or unusual to detect by optical means.


Project phases:

WP1: Fiber-optic flow sensors

WP2: Fluid level sensors and fluid level detectors

WP3: Microfluidic fiber-optic absorption/fluorescence spectroscopy systems based on all-fiber microcells

WP4: Fiber-optic sensors for gas composition detection through measurements gas’s refractive index

WP5: Optical sensors for other fluid properties determination


Project duration: 1.5.2017 - 30.4.2020                                                                                                            Project is funded by:ARRSLogo 2016 ang


Project leader: red. prof. ddr. Denis Đonlagić


University of Maribor, Faculty of Electrical Engineering and Computer Science:

 - red. prof. ddr. Denis Đonlagić (SICRIS)

 - red. prof. dr. Dušan Gleich (SICRIS)

 - asist. dr. Matej Njegovec (SICRIS)

 - doc. dr. Simon Pevec (SICRIS)

 - Uroš Povh (SICRIS)


 - Borut Lenardič (SICRIS)

 - Peter Lukan (SICRIS)