Tag: fiber Bragg gratings

Researchers have presented dynamic gratings used instead of depending on fixed-position fiber Bragg gratings, and now core-launched laser beam light can unite to the cladding modes of conventional optical fiber resulting in distributed fiber sensing of the external environment.

The thing is that fiber optic sensors allow distinguishing between chemicals and liquids external to the optical fiber, herewith, they are usually based on refractive-index changes in the cladding modes of the fiber. Moreover, fixed-position fiber Bragg gratings (FBGs) are applied to excite these cladding modes and unite laser beam light from the core mode.

Nevertheless, FBG sensors need specific equipment to create the gratings at the optical fiber, also they only work as point sensors at specific, predetermined locations. A team of researchers from Israel tries to overcome these challenges by developing dynamic gratings at reconfigurable short sections along with the optical fiber.

Thus, the new gratings are independent of any permanent change in the fiber structure. It is possible to switch them on and off at will, and fiber optic sensors based on dynamic gratings allow scanning along with the optical fiber. According to researchers, after the installation of a grating, its effect is not restricted only to light in the core mode.

Similar to conventional FBGs, the dynamic gratings also unite laser beam light between core and cladding modes. Herewith, in analogy to fiber Bragg gratings, such connection will occur for the light at very specific frequencies. “An optical probe wave of tunable frequency is launched at the dynamic grating, and the exact frequency in which coupling takes place is carefully noted.”

Compared to FBGs, dynamic gratings enable the researchers to carry out tests in any chosen position. It should be noted that the developed fiber optic sensors have been already tested over 2 m of traditional optical fiber. To be more precise, fiber sensors consisted of  8 cm length dynamic gratings perform scanning along with the optical fiber resulting in the combination of spectra between core and cladding modes in each position.

Measurements accurately detect the parts of optical fiber that were immersed in ethanol and water, herewith, the fiber sensors can distinguish between the two with an 8 cm resolution. At the same time, the refractive index outside the fiber is possible to estimate precisely with fourth-decimal-point accuracy (0.0004).

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, FBG interrogators and multiplexers, Distributed Acoustic Sensing (DAS) systems, Distributed Temperature Sensing (DTS) systems. The company creates and supplies a broad variety of fiber optic solutions for monitoring worldwide. If you are interested in structural health monitoring systems and want to learn more, please contact us at info@optromix.com

Researchers have been firstly created a fiber optic sensing system, known as a fiber Bragg grating (FBG), inside bio-soluble optical fibers. According to Science Daily, fiber optic technology can be used to monitor the condition of fractures and safely study sensitive organs, such as the brain.

Fiber Bragg gratings that reflect the light of a particular wave are often applied in optical fibers used as distributed sensors. For example, such fibers are employed to monitor bridges in real-time or to track the integrity of aircraft wings. However, they have not yet been used in medicine. The new fiber technology will overcome these limitations by using optical fibers that break down in the body.

Firstly, researchers from Greece and Italy have created biodegradable glass for FBGs. They used phosphorus oxide in combination with oxides of calcium, magnesium, sodium, and silicon to perform this. The resulting optical glass combines excellent optical properties with water solubility and compatibility with living organisms, and its properties can be changed by adjusting the chemical composition.

Then the fiber Bragg gratings made from biodegradable glass were placed in conditions that are similar to the human body. As the experiment demonstrated, the created structures dissolve without a trace in such an environment, which opens the way for their medical application. Such FBG sensors are considered to be safe for the body and will not need to be removed after their use.

Possible examples of using optical fiber with FBGs include creating fiber optic sensors to assess joint pressure and monitor the heart and other sensitive organs. This optical fiber can also improve laser techniques for removing tumors by simultaneously conducting a laser beam and measuring temperature, necessary for the laser ablation process. Nevertheless, its safety and effectiveness will be tested on laboratory animals before developing medical applications of FBG technology.

Thus, a group of engineers from the University of Connecticut has created a biocompatible pressure sensor that will help doctors monitor chronic lung diseases, brain tumors, and other medical conditions, and then dissolve into the human body without a trace. Such a FBG sensor should replace existing implanted pressure sensors that are made up of potentially toxic substances and require removal after use.

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

It is highly essential to have accurate spatial information of a medical device inside the patient for proper manipulation of the instrument. The thing is that a wide range of clinical applications requires spatial information. Nevertheless, each technique has its disadvantages, the promising solution is the application of fiber optic sensors in the catheter for its spatial information.

Fiber sensors are applied in various medical devices such as endoscopes and catheters. Such features as compact size, flexibility, lightweight, immunity to electromagnetic interference, and compatibility with medical imaging modalities make fiber optic sensors ideal for the medical environment. Therefore, FBG sensors are used in different studies to offer feedback from medical tools, they allow monitoring of muscle fatigue, cardiac activities, and body temperature.

Moreover, the application of fiber optic sensors also includes cardiovascular diagnosis, artery pressure detection, artery detection, intra-aortic balloon pumping, prostatic implants, and urology. For instance, FBG sensors are employed as force sensors to determine the interface between various tissues in order to help in precisely installing a catheter in the epidural space. 

Additionally, sensors based on FBG multicore fibers are used in numerous different shape sensing applications. “They have been used for 3D shape recognition of solid objects, shape recognition of flexible morphine wing, and curvature detection of a continuum manipulator.” Nowadays the studies describe the application of FBG sensors in single-core optical fiber but there are also FBG multicore fibers.

To be more precise, FBG multicore fibers can work as a curvature sensor and 3D shape sensors. Although their cost is higher than in single-core optical fibers, the cross-sectional area of the shape sensor with FBG multicore fibers is smaller than the shape sensor with single-core fibers. Herewith, certain devices require the use of FBG multicore fibers because of the limited space. Also, the cores of multicore optical fibers are mechanically coupled, and the relative distance between the cores remains constant, while they experience identical temperature. Such features of FBG multicore fibers make them more beneficial than single-core optical fibers.

Finally, fiber Bragg grating sensors (FBG) written on multicore optical fibers are applied as shape sensors for flexible devices. Several FBG multicore fibers have been uniquely tested as a shape sensor for a catheter. More particularly, 4 multicore optical fibers are applied despite a single multicore fiber with 3 or more cores that have FBG sensors is enough for reconstructing the shape of a flexible device. Several multicore optical fibers expand the reliability of the sensing system against individual FBG sensor failure.

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

Tunnel fires are not regarded as usual, however, they also can perform great damage to lives and properties if they take place. The process of fire detection inside the lengthy and curved tunnel is challenging. Nevertheless, fiber optic sensors based on fiber Bragg grating or FBG technology allows detecting tunnel fires and FBG sensors are considered to be a novel methodology that determines not only the presence but also locates the fire inside the tunnel.

To be more precise, FBG sensors are installed across the inner sides of the tunnel where they control it by the optical spectrum analyzer or wavelength division multiplexing sensor interrogator at the exit. “The change in the center wavelength from the original spectrum at the output denotes the temperature change (fire occurrence) inside the tunnel.” FBG fiber optic sensors offer output with more precision, herewith, fiber Bragg gratings can hold very high-temperature values.

It should be noted that it is possible to detect fires applying various ways, for instance, installing temperature sensors inside the tunnel or controlling the tunnel through the camera. Temperature sensors enable to sense of tunnel fires but their location presents difficulties. Moreover, such a temperature sensor as a thermistor can not stand very high temperatures (1000˚C) as well as there is a problem of self-healing.

FBG sensors, in their turn, provide a highly efficient process of sensing and locating. The thing is that fiber Bragg gratings in fiber optic sensors lead to a narrow range of wavelengths to shift and the rest of it to transmit through it. The center of the reflected wavelength is Bragg’s Wavelength. The features of FBG sensors allow measuring temperature or strain changes in the structures. Additionally, FBG fiber optic sensors have a greater temperature steadiness ability, more immune to electromagnetic interferences, longer lifetime, explosion safe and it is possible to be multiplexed.

Fiber Bragg grating is a short part of optical fibers that reflects a specific light wavelength and transmits all other wavelengths. FBGs operate as an optical notch filter. The operating principle is based on the Bragg grating patterns inside the fiber that perform the reflection. The design of fiber Bragg gratings includes holographic interference or a phase mask to undergo a short length of optical fiber to a periodic distribution of light intensity. 

The developed FBG sensors have been already tested and demonstrated the following results: the sensitivity value of the fiber optic sensor achieves 20 pm/˚C. Also, it is possible to increase the accuracy of fire location inside the tunnel by increasing the number of FBG fiber optic sensors for the considered tunnel length of 4 km. Thus, FBG technology can help to perform operations very fast and can save many lives and properties.

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

An electrical engineer from the Netherlands has developed a fiber optic sensor based on fiber Bragg grating technology (FBG)with a super-precision of less than the size of an atom. Such FBG sensors favor the production of smaller chips, which in turn are required to develop faster computers.

The developed fiber sensor allows measuring deformations less than the width of an atom is possible to be measured. Thus, these fiber optic sensors offer a highly promising application that enables to improve the accuracy of current machines. It should be noted that even the slightest deformation of the wafers in machines may result in serious problems.

“These wafers are actually quite stiff, but because they are moved about at such great speed, they are subject to g-forces that slightly deform them. Measuring this deformation by FBG sensors gives the opportunity to compensate for it in some or other way, and opens up the possibility of producing even smaller chips.”

This is the main reason why the engineer began developing a fiber sensor based on FBG technology, enabling sensing these deformations of roughly one nanometer per meter. The operating principle of this extremely precise FBG sensor is that it is possible to measure the deviations in the frequency of laser beam light with high precision, as well as the principle used by fiber Bragg grating – an optical fiber of sorts treated in such a way that it becomes opaque for a very specific color of light.

Herewith, such a resonance frequency is dependant on the extent to which the optical fiber is stretched. Therefore, fiber Bragg gratings can be employed here to the moving parts as a way to measure the wafer’s deformation. The fiber optic sensing system based on FBG technology has been already tested in the lab. Although modern machines require dozens of such fiber sensors, it is not a challenge because FBG sensors are not expensive and light-weight.

The engineer claims that it succeeded in achieving the accuracy of 5 nanometers per meter, thus, the fiber optic sensor of a few centimeters in length allows measuring the deformation of a couple of dozen picometers, herein, that is less than the diameter of an atom. Nevertheless, several challenges have to be overcome before this incredible level of precision could be reached due to fiber Bragg gratings.

The first challenge is a need for sophisticated stabilization techniques to provide that the laser beam light has the right frequency. However, the main problem is considered to be the resonance frequency of the FBG sensor that depends on not only the deformation but also the temperature. 

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

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

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.

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

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.

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

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.

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