Tag: fiber optic sensors

FBG sensors measure pH to study tissue growth

FBG sensors for pH measurement A team of researchers from the U.S. continues developing a fiber optic sensor based on fiber Bragg grating or FBG technology that helps to study tissue growth in the lab. The operating principle of the FBG sensor is based on a light-based signal to measure pH that is considered to be a highly important quality in cell-growth studies.

It should be noted that compared to traditional sensing systems, it is possible to use the fiber sensor to control the environment in cell culture for weeks at a time without the necessity to bother the cell-growth environment. For several years, the researchers have designed photonic sensors that apply optical fibers etched with a fiber Bragg grating (FBG). Temperature or pressure changes lead to transform the wavelengths that are able to get through the fiber Bragg grating.

Such a sensing system has been already tested and shows that fiber sensors with Bragg gratings can be easily adapted to pH measurement. The application of a fiber optic-based platform featuring FBGs promotes the development of a fiber optic sensor that “measures the heat released by pH-sensitive chromophores upon absorption of light”.

Thus, due to this fiber sensing system, the researchers have succeeded to compare visible light absorption by the chromophores to the heat released and changes in the fiber Bragg grating signal over a pH range of 2.5 to 10. To be more precise, firstly, the team fills a petri dish with a solution made with red cabbage juice powder that transforms color in response to changes in pH. Then the researchers put one optical fiber above the dish, connecting the optical fiber to a laser pointer, and shine the laser beam into the sample.

Additionally, they install a second optical fiber with FBGs as the temperature sensor in the cabbage juice solution. Herewith, the team controls manually the pH levels in the solution. Shining the solution above, it absorbs the laser beam to different degrees depending on its pH level. The fiber optic sensor operates as a thermometer and detects these tiny changes in the juice’s heat.

A second color into the solution added by the researchers demonstrates that the fiber sensor offers its operation over a wide range. Moreover, further researchers show that the pH measurements by the FBG sensor are precise to plus or minus 0.13 pH units and are stable for at least three weeks.

Finally, it is planned to perform tests on “how cell cultures are affected by the slight, temporary temperature changes (about 1 to 2 kelvins) in localized areas of the sample that occur as a result of this measurement technique” by applying the developed fiber sensing system. Also, the temperature changes are required to reduce in the future as much as possible because over time the fiber sensors could be developed to control the growth of tissue in the human body

Optromix is a manufacturer of innovative fiber optic products for the global market. The company provides the most technologically advanced fiber optic solutions for the clients. Optromix produces a wide range of fiber optic devices, including cutting-edge customized fiber optic Bragg grating product line and fiber Bragg grating sensor systems. Moreover, Optromix is a top choice among the manufacturers of fiber Bragg grating monitoring systems. If you have any questions, please contact us at info@optromix.com

Fiber optic sensors make cities “smarter”

FBG sensors for smart cities Companies from the U.S. and Japan have developed for the first time a new fiber optic sensing technology that allows delivering traffic-related data to smart cities without tearing up streets. To be more precise, in smart cities connected intersections and traffic fiber optic sensors play a crucial role in the whole infrastructure.

Thus, the combination of intersections with fiber sensors may greatly affect improving traffic flows resulting in congestion and pollution reduction, finally, improving life quality, resident safety, and raising economic activity and productivity. Additionally, these fiber optic sensors may promote pedestrian safety and save lives in different cities.

It should be noted that data information on traffic patterns and road congestions required to make the best application of such fiber sensing systems. Fiber optic technology makes it possible to get the data without physical inspections, putting in new infrastructure, or tearing up streets.

The concept has been already tested and demonstrated the opportunity to apply network infrastructure with existing fiber optic cables already installed in the ground as distributed optical sensors to compile data on city traffic patterns, road conditions, road capacity, and vehicle classification information.

Nowadays it is planned to enlarge tests of the fiber optic sensing technology and to decide how it can be employed in smart cities. The main purpose of technology is regarded as to enable “existing optical fiber providers to deliver smart city traffic-related data without tearing up roads or sidewalks”

The manufacturers apply new fiber optic technology and combine fiber sensors with artificial intelligence-based software to provide “intelligent traffic monitoring including the sensing of vehicle density, direction, speed, acceleration, deceleration and more”. The thing is that until recently it was required to install purpose-built optical fiber in very shallow spaces in the ground with fiber Bragg grating at predetermined intervals to collect and analyze this type of data information.

Today the proposed fiber optic solution suggests utilizing optical fibers already in the ground. The representatives of the companies confirm that these fiber optic sensors may lead or improve various public functions, for example, they allow first responders to identify and respond to gunshots as well as increasing municipalities’ capability to more quickly and efficiently detect earlier deterioration of bridges, tunnels, and other infrastructure.

Application of a single FBG interrogator in the distributed multi-parameter fiber optic sensor system estimated different characteristics of back-scattering light, which can be utilized to determine the static strain, dynamic strain, acoustics, vibrations, and temperatures for each optical fiber segment.

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Embedded fbg strain sensors for robotic applications

FBG strain sensors for robots Fiber optic technology continues to find new applications in various fields including medicine, biomechanics, space, oil industry, geophysics, etc. According to researchers from the U.S., fiber optic sensors are regarded as uniquely suited for utilizing in robotic hands. To be more precise, the researchers have developed a three-fingered soft robotic hand with multiple embedded fbg strain sensors resulting in emerging of a new type of stretchable fiber sensor.

The application of fiber optics allows installing 14 fbg strain sensors into each of the fingers in the robotic hand, therefore, it can “determine where its fingertips are in contact and to detect forces of less than a tenth of a newton”. Moreover, the researchers confirm that the new stretchable optical sensing material could find highly promising application in a soft robotic skin to offer even more feedback in the future.

Modern robotic hands include more strain sensors than is typical today, thus, they can operate autonomously and react safely to unexpected forces in everyday environments. It should be noted that human skin consists of thousands of tactile sensory units only at the fingertip, while a spider has about hundreds of mechanoreceptors on each leg, however, nowadays conventional humanoid includes only 42 fiber sensors in its hand and wrist.

Herewith, it is difficult to add traditional force or pressure sensors because of complex wiring, it is prone to breaking and susceptible to interference from different electromagnetic tools. Nevertheless, it is possible to embed several fbg strain sensors in a single optical fiber. The operating principle of such a robotic hand is based on several fiber sensors in each of the fingers that are connected with 4 optical fibers, through a single fiber can be used for this purpose.

Additionally, the embedded fbg strain sensors offer such an advantage as the immunity to electromagnetic interference. Other benefits of FBG sensors include:

Fiber sensors are passive and can be used in explosive environments.
Non-conductivity of fibers.
Opportunity to install more than 80 fiber sensors per optical fiber.
The fast response of FBG sensing systems.
Fbg strain sensors do not corrode and have a small diameter.

Robots used in the industry provide extremely accurate manipulation with only limited fiber sensors, herein, they operate in controlled environmental conditions where people do not risk to do it. Nevertheless, the development of soft robots, which will interact routinely and safely with people, require careful attention to tactile and force sensing. That is why fbg strain sensors are considered to be a perfect fiber optic solution.

Optromix is a manufacturer of innovative fiber optic products for the global market. The company provides the most technologically advanced fiber optic solutions for the clients. Optromix produces a wide range of fiber optic devices, including cutting-edge customized fiber optic Bragg grating product line and fiber Bragg grating sensor systems. Moreover, Optromix is a top choice among the manufacturers of fbg strain sensors. If you have any questions, please contact us at info@optromix.com

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Compact FBG sensors control traffic density

FBG sensors for traffic control A new compact sensing system based on fiber Bragg grating technology has been designed to control urban traffic density up to 80 kph. The sensing technology includes a 2.5-m-long and a 2-cm-high fiber optic sensor made from a combination of silicone addition rubber and fiber Bragg grating put inside a carbon tube.

The design of the compact FBG sensors allows monitoring and detecting the traffic density and car crossing in a single lane. It should be noted that such a sensing system has been already tested in real traffic and demonstrated quite a high detection rate of 98.946% based on the control of 1518 vehicles of various types and sizes.

To be more precise, traffic sensing systems are considered to be special devices that determine input data and information for other transport infrastructure systems. It is possible to install traffic sensors next to, above, into, or onto a road’s surface. The fiber optic sensors control “the presence of a vehicle, vehicle speed, vehicle classification, wheelbase and number of axles, total vehicle weight, road axle load, and occupancy, all of which indicate the traffic flow quality”.

The thing is that sensing systems based on optical fibers provide the following benefits: robustness, precision, high sensitivity, electromagnetic and chemical resistance, electrical passivity, and a broad temperature operating range. Additionally, it is possible to use fiber optic sensors in hybrid systems. The operating principle of fiber sensors is based on transmitting and receiving a laser or infrared beam from an emitter to a receiver.

Another type of fiber optic sensor is distinguished which is a micro-motion one. Such a fiber sensor operates using the increasing of optical fiber attenuation. Herewith, these optical fibers have special protective coatings and they are installed into a roadway. Nevertheless, their application is experimental, and these fiber sensors are not employed in general practice.

Also, the DAS technology (Distributed Acoustic Sensor) can be used for the same purposes. For instance, DAS systems apply a single optical fiber to control multiple traffic parameters, such as detecting a car, its direction, its speed, etc. However, FBG sensors require proper protection in order to avoid damage to the sensors. The use of composite fiber protection to the FBG sensors enables us to successfully solve the current problem.

The high sensitivity of portable FBG sensors and success rates in determination vehicles are regarded as a good supposition for expanding research and future developments for monitoring automotive traffic. Nowadays researchers plan to improve the design of fiber sensors to provide a more stable sensitivity, as well as to expand the determination capabilities of the sensing system, and to produce the sensor for year-round application.

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A new application of FBG sensors

new FBG sensors A team of researchers offers a new application of fiber Bragg grating sensors (FBG sensors) in the construction and characterization of Micro Pattern Gaseous Detector. Such a FBG sensing system includes 144 gas electron multiplier chambers of about 0.5 m2 active area each. It should be noted that FBG technology has been applied in high energy physics only for high precision positioning and re-positioning fiber sensors due to their benefits (low cost, easy installation, low space consumption). Nowadays the most common application of fiber Bragg gratings remains the use for very accurate strain measurements in material studies.

Now FBG technology is used as flatness and mechanical tensioning sensors employed to the wide GEM foils of the GE1/1 chambers. FBG sensor array allows detecting the optimal mechanical tension applied and characterizing the mechanical tension that should be applied to the foils. A new application of FBG sensors has been already tested and demonstrated great results that can determine a standard assembly procedure and possible future developments.

Fiber Bragg gratings are considered to be a type of distributed Bragg reflector, developed by a short segment of optical fiber that enables one to reflect certain wavelengths of light and transmit all others. The operating principle of FBG sensors is based on “the creation of a periodic variation in the refractive index of the fiber core, which generates a wavelength-specific dielectric mirror”. Thus, the FBG sensing system can be applied as a strain measurement device because changes in fiber Bragg gratings lead to various light frequency responses.

One more application of FBG sensors in GEM chamber construction includes the opportunity to be applied as a load gauge for accurate measurement of the tensile load employed to the foils, of the various layers, at the same moment. The thing is that this FBG application plays a crucial role in the case of the GE1/1 chambers because the foils are stretched through screwing nuts with a dynamometric screwdriver during their assembly procedure, therefore, it is necessary to know accurately how much to strain the foils to escape to stretch them too much.

The testing of fiber Bragg grating sensors consist of proper stretching of the GE1/1 GEM stack, then the researchers removed a single stretching screw from the chamber and replaced it with an eyelet screw with installed stainless steel wire applied to set various weights. Additionally, it was necessary to add weights in different steps until they applied load achieves in the fiber Bragg gratings facing the eyelet the same response as when stretching of the GEMs occurs by the traditional screw.

Finally, the technology of FBG sensors is regarded as a highly reliable glue-less technique that offers the correct tensioning of the three GEM foils. The correct tension across the GEM stack leads to uniform gaps resulting in the required performance of the detector. Moreover, FBG sensors operate successfully as load gauges for accurate detection of the used stretching force to GEM foils.

FBGs fiber Bragg gratings fiber optic sensors

Fiber optic sensors based on the vapor deposited conducting polymer

polymer FBG sensors A team of researchers from Australia has developed a mathematical model, which is based on energy deposition and the laser-induced damage threshold (LIDT) for low-intensity light radiation resulting in the appearance of conducting polymers in novel fiber optic sensing applications.

It should be noted that nowadays polymer features are regarded as one of the most potentials and studied CP’s, herewith, the material may find numerous applications such as light-emitting diodes (OLED), optical displays, photovoltaic devices, and fiber optic sensors.

The thing is that the poly(3,4-ethylene dioxythiophene) is almost visibly transparent in its doped state, while it converts into an opaque material (dark blue) in the dedoped state, thus, making the polymer ideal for optical applications, for instance, in electrochromic devices and optical fiber sensors.

The interaction between light and the sensing material plays a crucial role in fiber optic sensing. To be more precise, there is a reaction between the sensing material and an external stimulus, therefore, it becomes possible to interrogate and measure the change, linking the optical fiber measurement to the external stimuli.

Optical fibers are considered to be an ideal example of a way to send light to a volume or point of interest for fiber optic sensing. Usually, “optical material is coated on the side or at the tip of the fiber, which are typically inorganic material”. Numerous recent sensing applications (temperature sensors, hydrogen sensors, and polymer functionalization of exposed-core microstructured optical fibers) include fiber tip fabrication and side coating.

Thus, the researchers present a new fiber optic sensing architecture based on coating the tip of an optical fiber with the vapor-deposited conducting polymer. They confirm that such fiber optic sensors enable us to study the unique electrochemical properties of PEDOT: Tos at the sub-micron length scale. Additionally, the polymer material can be integrated with optical waveguides (optical fibers as well) resulting in a range of electro-optical devices.

Optical fibers provide such benefits as immunity to electromagnetic fields, the possibility for in-vivo, and distributed measurements with the electrochemical properties of poly((3,4-ethylene dioxythiophene). Also, the researchers prepare a technique to gradually deposit PEDOT: Tos layers with desired thicknesses on the tip of optical fibers to produce such a fiber optic sensor.

Finally, the fiber optic technology was tested, and the polymer material was deposited at the tip of cleaned and cleaved SMF-28 optical fiber. Moreover, the deposition technique is based on 4 steps: “ 1. Oxidant solution preparation, 2. Oxidant coating and splitting at the tip of the fiber, 3. VPP process and 4. Washing of unbound and unreacted monomers”.

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FBG sensors for measuring human body temperature

FBG sensors for temperature measurement The opportunity to measure body temperature plays a crucial role in both physiological studies and clinical investigations. New wearable sensors based on fiber Bragg grating or FBG technology offer such an opportunity in intelligent clothing for human body temperature measurement.

The main purpose of the development is the integration of FBG sensors into functional textiles to enhance the abilities of wearable fiber optic solutions for body temperature monitoring. Thus, the FBG sensing system provides a temperature sensitivity of 150 pm/°C, which is almost 15 times higher than that of a bare fiber Bragg grating.

It should be noted that fiber Bragg grating is regarded as a type of distributed FBG reflector installed in a short segment of optical fiber that reflects particular wavelengths of light and transmits all the others. The FBG technology is used here as an inline optical filter to block specific wavelengths, or as a wavelength-specific reflector.

Additionally, FBG sensors offer great benefit over electronic sensing systems for the use in intelligent structures, civil engineering, harsh environmental conditions, built structural health monitoring system and other. Distributed temperature sensors based on fiber Bragg gratings measure human body temperature at fiver places: left chest, right chest, left armpit, right armpit, and at the center of the upper back. Herewith, the data information provided by these FBG sensors at five places is not the same because different parts of the human body have different temperatures.

The application of distributed temperature sensors based on FBG technology allows developing a sample of intelligent clothing and testing the heat transmission mechanism from numerous aspects. A new mathematical model of heat transmission for the human skin, the air and clothing has been created. Therefore, FBG sensors provide the theoretical basis of human temperature measurement applying intelligent clothing with distributed temperature sensors and demonstrate the implementation of optical fiber grating into the clothing.

Finally, the temperature measured by DTS systems can be useful to represent human body temperature in clinics. Nonetheless, it is planned to enlarge “research in intelligent clothing to cover the measuring and recording of real-time physiological information, such as human respiration, heartbeat, blood pressure, and other physiological signals.”

The biomedical application of wearable FBG sensors, which are non-intrusive, non-invasive, and continuously being monitored, is considered to become a highly potential monitoring and diagnostic devices. Thus, these distributed temperature sensors can determine and process physiological signals, extract signal characterization, transmit data, and have other basic options.

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FBG accelerometers for railway structural health monitoring

FBG accelerometers for railway monitoring New improved accelerometers based on fiber Bragg grating or FBG technology by fiber optic sensors allow performing railway structural health monitoring in both frequency and acceleration range. Such FBG accelerometers provide such advantage as immunity to electromagnetic interference, herewith, the fiber accelerometer offers multiplexed data information along very long lengths of a railway or pipeline for the in situ single-headend measurements of such parameters as vibration, strain, temperature, and fault locations or other challenges.

Thus, distributed sensors based on fiber optic technology are considered to be a better sensing device for structural health monitoring, compared to other sensing systems. It should be noted that FBG accelerometer systems are able to perform “perimeter security and other applications where events span frequencies <700 Hz and acceleration shock values of <30 G with sensitivities of about 16 pm/G” among various fiber optic sensing systems.

Nevertheless, the application in railway structural health monitoring requires optical fiber sensors that offer a higher level of acceleration peak value and broader frequency ranges. The developed optical fiber accelerometer offers the following parameters: >40 G acceleration values, 8 pm/G sensitivity for frequency values up to 1 kHz and the device is operable up to 2.5 kHz. The developed fiber optic sensor was already tested in a railway application and demonstrated successful results.

Additionally, it is possible to change the optical fiber cross-section to make the stress-induced measurement optimized, depending on the required parameters. For example, this FBG accelerometer has a commercially available length (about 0.35 m), a 15 mm diameter, 50/50 splitter (3 dB coupler), a 56 g stainless-steel mass (25 mm diameter, 15 mm height).

The principle of FBG accelerometer operation is based on the lateral forces cause birefringence changes that directly correlate with force parameters, such as vibration. Therefore, the FBG accelerometer installed on a moving train enables to monitor of the reflection spectrum in real-time to determine various problems with the track of a railway such as cracks, corrugations, or weak points.

Finally, the developed microstructured optical fiber used in new types of FBG accelerometers increases the level of measurement sensitivity of available systems up to 5X, and it is planned to apply the optical fiber to manufacture additional FBG accelerometers for field tests. Herewith, the FBG accelerometer is regarded as a highly important sensing device in an all-optical fiber sensing network that offers a great amount of data information resulting in efficient structural health monitoring of railways.

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FBG sensors in Biomechanics and Rehabilitation Application

FBG sensors in biomechanics Nowadays the technology of fiber Bragg gratings is considered to be quite attractive for sensing applications in biomechanics and rehabilitation engineering fields thanks to the proposed FBG benefits such as compact size, lightweight, biocompatibility, chemical inertness, multiplexing capability, and immunity to electromagnetic interference.

Additionally, FBG technology overcomes other traditional technologies for the measurement of a range of physical parameters or for the performance of high-sensitivity biochemical analysis because fiber Bragg gratings offer a high-performance alternative to conventional sensing devices.

It should be noted that the sensing application of FBG sensors includes such areas as aeronautics, automotive, civil engineering structure monitoring, and undersea oil exploration. Nevertheless, the use of FBG sensors in biomechanics and rehabilitation is quite novel and it still requires its practicality for full-scale implementation.

The potential application of FBG technology may include the following fields: strain detection in bones, “pressure mapping in orthopedic joints, stresses in intervertebral discs, chest wall deformation, pressure distribution in Human Machine Interfaces (HMIs), forces induced by tendons and ligaments, angles between body segments during gait, and many others in dental biomechanics”.

FBG sensors demonstrate great potential for biomechanics and rehabilitation engineering thanks to their benefits, thus, making FBG technology suitable for a human body. To be more precise, fiber sensors are able to adapt to the body, so it is possible to employ them for in vivo measurement and to left for long-term monitoring.

Moreover, fiber Bragg gratings can change traditional sensing technologies such as electrical strain gauge (ESG), piezoelectric, resistive, or another solid-state sensing, both for measuring physical characteristics or for carrying out high-sensitivity biochemical analysis. The development of FBG continues, and it is possible that very soon new FBG sensors with improved characteristics appear.

If you want to obtain a highly efficient sensing system, you should choose the Optromix company. Optromix is a manufacturer of innovative fiber optic products for the global market. The company provides the most technologically advanced fiber optic solutions for monitoring worldwide. Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line such as fiber Bragg grating sensors, FBG interrogators and multiplexers, distributed acoustic sensing (DAS) systems, distributed temperature sensing (DTS) systems. The company provides a wide range of sensors: temperature sensors, strain sensors, displacement sensors, tiltmeters, accelerometers. If you are interested in FBG sensors and want to learn more, please contact us at info@optromix.com

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Space application of FBG sensors

FBG sensors for space application Fiber Bragg grating sensors are highly useful fiber optic sensing devices that help carry out the monitoring of temperature and strain characteristics even during a nanosatellite mission. FBG sensors present highly attractive reliable fiber optic solutions for process monitoring in a spacecraft. Additionally, it is possible to install these fiber sensors in composite structures or attached on their surface for structural health monitoring during the entire life cycle of a satellite.

To be more precise, space application of fiber optic sensors requires the use of two fiber Bragg gratings to measure temperature and strain characteristics during one space mission. The main aim of the mission is the validation and demonstration of the suitability and reliability of fiber optic technologies when it comes to a small area with numerous restrictions in terms of mass and power consumption.

Despite the fact that FBG sensors offer great performance in various fields of application, especially in industry, engineering and science, however, the use of fiber sensors in space application is not so popular, although fiber optics are presented more than 30 years in space but typically applied to transmit data or to guide the light for illumination purposes.

Fiber sensors based on fiber Bragg grating technology have numerous benefits such as electromagnetic immunity, the possibility of multiplexing, and weight-saving by taking copper harness away. This is the reason why fiber sensing technology is perfect for the harsh space environment.

Also, FBG sensors are better than other optical fiber sensors because their optical response does not depend on the optical power of the light source the eventual loss of energy transmitted along with the optical fiber, and of the response of the photodetector, thus, the response of the fiber sensor is considered to be wavelength-coded.

The used FBG technology has been successfully tested and the tests presented the capability and reliability of fiber optic sensors based on fiber Bragg gratings in space environmental conditions. In spite of the high restrictions in terms of mass, volume, and power consumption, FBG sensors offer an optimal performance of all-optical fiber components after their 3 years’ application in the space environment.

Finally, during the whole space mission crucial attenuation proving the degradation of fiber optic components because of harsh environmental conditions (as well as radiation and vacuum conditions) has not been registered. Herewith, the used tunable laser system for telecommunications purposes also presented excellent results in the space environment. It is possible that these FBG sensors contribute to the creation of more complex sensor arrays with a more complex FBG interrogator unit that will enable better resolution and operation in a wider temperature range.

If you want to obtain a highly efficient sensing system, you should choose the Optromix company. Optromix is a manufacturer of innovative fiber optic products for the global market. The company provides the most technologically advanced fiber-optic solutions for monitoring worldwide. Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line such as fiber Bragg grating sensors, FBG interrogators and multiplexers, distributed acoustic sensing (DAS) systems, distributed temperature sensing (DTS) systems. If you are interested in FBG sensors and want to learn more, please contact us at info@optromix.com

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