Articles

about Fiber Bragg Gratings (FBG), FBG Sensors and Monitoring Systems

Space fiber optic application: a short overview

on September 21, 2020

Space fiber optic application: a short overviewNew fiber optic solutions provide high-definition and fast fiber optic systems for sensing that become very promising in several space applications. Such advantages as composites in design and lightweight materials make fiber optic sensors highly important for the aerospace industry leading to a great requirement in non-destructive testing.

To be more precise, the development of advanced materials results in the fact that fiber optic sensors are considered to be essential in the design, production of aerospace vehicles, as well as their non-destructive testing. Fiber sensors are regarded as systems with flexible, low-profile optical fibers that do not need electrical sources.

It is possible to use fiber optic systems at sharply curved areas installed within devices or mounted directly to electrical components. Even though fiber optic sensors are compact and lightweight, they allow for distributed sensing directly stress, strain, acoustic, or temperature.

Compared to conventional strain gauges, fiber optic applications offer critical information with high density and low additional cost for various measurement points. A company-manufacturer of fiber optic systems from the U.S. has presented fiber sensors for aerospace industries.

Such fiber optic sensors perform more than 1,000 strain or temperature sensing per meter of a conventional compact, lightweight sensors. Additionally, “the high definition data can fully map the contour of strain or temperature for a structure under test or during manufacturing.”

These fiber sensors are suitable for dynamic applications or where lower sensor density is needed offering high-speed multipoint sensing, with tens or hundreds of fiber optic sensors on versatile optical fibers that cover long distances. Herewith, they provide the opportunity to perform several measurement types, for example, strain, temperature, vibration, or displacement by a single optical fiber.

Fiber optic applications include the aerospace industry and offer a more detailed design validation at every stage of the structural integrity building block process. It should be noted that composites provide a high level of strength-to-weight ratios. Nevertheless, new devices for validating the performance of fiber sensors are needed for their unique properties.

The compact size and distributed sensing of fiber optic sensors enable in-situ characterization for coupon testing, curing process validation, components/module testing as well as full-scale structural health monitoring of complex structures. It is possible to apply these fiber sensors in the predictive maintenance of smart elements.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, for example, fbg strain 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

read more
editorSpace fiber optic application: a short overview

New FBG sensors with copper and aluminum coatings

on September 7, 2020

New FBG sensors with copper and aluminum coatingsResearchers-manufacturers of fiber optic solutions from the U.S have presented new fiber Bragg grating sensors (FBG sensors) with copper and aluminum coating. Herewith, this fiber optic system has a compact size, it is hermetically sealed, and can maintain high temperatures leading to new opportunities for metal-coated fiber optic sensors.

To be more precise, FBG sensors and gold-coated sensors allow for developing new “inherently humidity-proof strain, temperature, displacement, acceleration, pressure, load, tilt, bio, and other useful fiber sensors and systems.” The researchers claim that FBG technology is considered to be very useful for numerous sensing applications in harsh environmental conditions because of its benefits provided.

The benefits of FBG sensors include the ability of absolute temperature measurement, rapid response, numerous sensing points on a single optical fiber strand with minimal mechanical burden and intrusion, as well as EMI immunity, spark-free, and chemical inertness.

Nonetheless, such conditions as a high level of humidity or temperatures, corrosive chemicals, or strong mechanical stress often presented in real environmental conditions create obstacles for fiber optic sensors with glass coating. New FBG sensors with copper, aluminum, and gold coatings enable researchers to enlarge current applications and develop new ones.

It should be noted that such processes as stripping and recoating are necessary for all laser writing methods included metals. The researchers demonstrate a robust technique to produce fiber sensors with acrylate, polyimide, aluminum, copper, and gold coatings installed into conventional high-temperature fiber Bragg gratings, which then are recoated with acrylate, polyimide, or gold coatings. 

Thus, such FBG technology makes it possible to change lengths of window stripping and recoating as well as control material thickness and length. Different types of inscription and coating allow for employing FBG sensors in different conditions from the cryogenic temperature of -200℃ to the high temperatures of +1000℃. 

These FBG sensors have a metal coating, and they are created by excimer and/or femtosecond laser writing methods. Additionally, the fiber optic system has been already tested, and the results show specific benefits in offering multipoint and multifunction sensing abilities in a constantly expanding range of applications not previously addressable by standard FBGs. The thing is that the coating of properly designed fiber optic sensors plays a crucial role in the integrity, survivability, functionality, and durability of FBG sensors.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, for example, fbg strain 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

read more
editorNew FBG sensors with copper and aluminum coatings

Seismic application of FBG sensors

on August 31, 2020

Seismic application of FBG sensorsA team of researchers presents a fiber optic technology based on fiber Bragg gratings (FBGs) for sensing to monitor the activity of an active volcano. The monitoring of volcanic activity plays a crucial role in better understanding and even prediction of important and potentially disruptive volcanic events, therefore, the fiber optic sensing system has to maintain harsh environmental conditions.

Nonetheless, the recording process of seismic activity now faces several difficulties concerning both discriminating between various sources of seismic wave, and the design of fiber optic sensing systems that can operate in active volcanic settings without any damages.

The team of researchers from France demonstrates the results obtained from the first high-resolution seismometer based on FBG sensors installed on an active volcano. It should be noted that the lifetime of modern fiber optic systems is quite short during their operation at high temperatures and the billowing, sulfurous, acidic gases near a fumarole.

Additionally,  standard FBG sensors can fail in emergency deployment, or repair, even in pre‐eruptive phases. The operating principle of novel fiber optic sensing systems is based on interferometry forms that apply more sensitive fiber optic elements such as fiber Bragg grating resonators that enable to detect the acceleration of the ground as a change in the signal from the FBG sensor.

These fiber optic systems can be used for networking across long distances and monitoring these distance via optical fibers. The FBG sensor is considered to be “a purely optomechanical geophone that is interrogated through a 1.5-kilometer fiber optic cable by a remote, and thus it is a much safer fiber optic system down the volcano’s flank.”

Moreover, the fiber optic sensing system has been already tested and recorded tiny seismic events within the volcano for nine months. The development of new FBG sensors lasts almost a decade, the researchers use previous researches of a high-resolution optical seismometer prototype that includes a 3-kilometer fiber optic cable. 

Finally, FBG sensors are regarded as highly reliable, fiber optic technology allow installing the sensors in locations that were not previously practical, providing more data about microseismic events under a volcano’s dome. The researchers claim that such fiber optic sensing systems offer more detailed information about “the fumarole signature, which helps to constrain the geometry and activity of the plumbing system of the dome”.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, for example, fbg strain 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

read more
editorSeismic application of FBG sensors

Fiber optic sensors in healthcare applications

on August 25, 2020

Fiber optic sensors in healthcare applicationsFiber optic sensors of different physical quantities based on fiber Bragg gratings (FBGs) find its popularity and they are actively used in various fields of industry to solve a variety of engineering problems. The general operating principle of such fiber sensors is based on a change in the FBG wavelength under the action of external impacts.
It should be noted that nowadays the population presents specific requirements to the application of assistive technology and, in particular, towards novel healthcare tools and fiber optic sensors. For instance, novel fiber sensors offer such benefits he electromagnetic field immunity, high flexibility, high sensitivity for mechanical parameters higher elastic limits, and impact resistance.

To be more precise, such benefits of fiber optic technology comply ideally with the instrumentation requirements of numerous healthcare tools and in movement analysis. Additionally, fiber optic sensors are considered to be lightweight, compact, stable to chemical substances, and they have also multiplexing capabilities. Therefore, fiber sensors are regarded as safe technology suitable for industrial, medical, and structural health monitoring applications.

The thing is that fiber optic sensors allow measuring various parameters, for example, angle, refractive index, temperature, humidity, acceleration, pressure, breathing rate, oxygen saturation, etc. It is even possible to install optical fibers in textiles for sensing applications, as well as incorporate them in composite metals, concrete and etc.

The development of fiber sensors based on fiber optic technology leads to high demands for healthcare systems, especially because of the population aging. The appearance of new medical systems results in higher demands on the fiber sensors’ performance because reliable control strategies require a robust fiber optic sensing system.

The modern fiber optic sensor should be tiny, herewith, saving its flexibility and compactness as possible. Herewith, intrusive sensing systems have higher requirements – they also need for biocompatibility, this is the reason why fiber optic technology continues developing to overcome the current challenges and provide high performance of novel healthcare systems and tools.

The increasing demands on fiber optic sensors and the fast development of the technology result in the appearance of numerous sensing systems for healthcare and medical tools. The fiber sensors enable to examine bones decalcification and strain distribution, evaluation of intervertebral disks, dental splints, cardiac monitoring, and pathologies detection.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, for example, fbg strain 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 

read more
editorFiber optic sensors in healthcare applications

Distributed acoustic sensing detects polar bears

on August 17, 2020

Distributed acoustic sensing detects polar bearsNowadays cases, when people meet polar bears, have dramatically increased especially in arctic areas because the environment continues rapidly transforming. Thus, there is a need for a structural health monitoring system that allows detecting bears to decrease the number of such meetings. Distributed acoustic sensing (DAS) is an ideal technology to perform this task.

DAS systems are used as an intrusion detection system that is able to operate in environments where temperatures fall to -70 C. Usually, the installation of the distributed acoustic sensing system takes place on the ground, that is why DAS system performance requires its testing in the snow. The DAS has been already tested at similar conditions (deep snow and extreme cold), herewith, people helped to imitate polar bears walking near the distributed acoustic sensing system.

It should be noted that standard DAS system consists of the following components:

  • a sensing fiber optic cable that can be stretched over long distances;
  • a laser central processing unit (DAS).

The operating principle of fiber optic technology is based on mechanical vibrations that undertake fiber impingement, leading to laser beam backscatter and therefore, allowing researchers to measure the signal required. 

The researchers planed to test several opportunities provided by the DAS system: the ability of optical fiber to maintain extreme temperatures, the suitability of distributed acoustic sensing to snow coupling. The performance of the DAS system has been tested at the temperature of the -70C in the MTS environmental control chamber, and it demonstrated good results.

“Launch boxes with 2200m of spooled fiber optic cable were applied on either side of the 150m of distributed acoustic sensing cable to imitate a field deployment of 4.5km.” The researchers pay careful attention to four separate test temperature ranges provided by the DAS system, they even calculate shoe surface area combined with the weight of the participants in order to learn human foot pressure and connect it with polar bear foot pressure to classify bears of different sizes.

Additionally, DAS also allows differentiating humans from polar bears. The thing is that polar bears generally walk with 3 points of ground contact, while people need only one point. Even though the feet of polar bears are quite large, researchers can easily offer similar foot pressures.

Finally, the test results of distributed acoustic sensing demonstrate that fiber optic cables can maintain extreme cold temperatures in the arctic regions, where the temperature is required not to disturb optical fiber performance. The DAS system detects signals at depths of at least 0.65m in the unprocessed data.

Optromix is a DAS system manufacturer that provides top of the line distributed acoustic sensing systems suitable for monitoring of commerce networks. If you have any questions or would like to buy a DAS system, please contact us at info@optromix.com

read more
editorDistributed acoustic sensing detects polar bears

Various fiber optic coatings for fbg strain sensors

on August 11, 2020

ricardo-gomez-angel-geBHIpvA6us-unsplashDistributed fiber optic strain gauges are known for their crucial advantages compared with traditional measurement techniques, for instance, inductive displacement transducers, etc. To be more precise, fbg strain sensors are corrosion resistant, dielectric, and insensible to electromagnetic radiation. 

It should be noted that any part of optical fibers is applied as the sensing element for the fiber optic strain sensors, herewith, the measurement is not limited by a specific section. Moreover, fbg strain sensors provide one more benefit that includes the opportunity of installing the optical fiber into the building material matrix.

Such a fiber optic sensing system allows detecting strain within concrete elements, which can include data about the curing and load behavior. The thing is that distributed fiber optic strain gauges play an important role in massive concrete structures, for example, foundations or concrete roads, therefore, these fbg strain sensors demonstrate the structural and loading conditions.

Herewith, such a fiber optic technology enables to combine the quality management of posttreatment and health monitoring. The operating principle of fbg strain sensors is based on the use of optical fibers, the core of which detects the strain. Also, it is necessary to pay careful attention to two techniques that influence the deformations of the fiber optic sensors: “slippage can occur between the fiber cladding (the so-called coating) and surrounding substrate; depending on the coating material, the cladding cannot wholly transfer the strain from the substrate to the fiber cladding and the core.”

Finally, optical fiber coatings are also important, therefore, different teams of scientists have analyzed their effect on strain transfer during matrix measurements. For instance, such a technique as Brillouin scattering shows that fiber optic cables have lower strain values in the matrix than the reference technique. Herewith, there are the strain transfer rates of embedded FBG sensors in mortar prisms.

The fiber optic technology has been already tested. The team installed the optical fiber into a reinforcing bar, which was later installed in the concrete. Herewith, a brass frame and optical fiber with a single-layer polyimide coating allow researchers to install the fiber in small concrete specimens and obtain similar values to the reference sensing measurements.

Additionally, distributed fiber optic sensors demonstrate higher values than the standard strain gauge measurements on the surface.  The researchers claim that the concrete is required to be quite cured to provide the strain transfer in the fiber optic sensors. However, the acrylate coating has higher strain losses.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) product line such as fiber Bragg grating sensors, for example, fbg strain 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

read more
editorVarious fiber optic coatings for fbg strain sensors

Fiber optic sensing solutions for extreme conditions

on August 3, 2020

jennifer-latuperisa-andresen-U1y2ye6nPks-unsplashElectrical sensing systems (strain sensors, string-based, potentiometric, etc.) have been the main method of measuring physical and mechanical phenomena for decades. Despite their widespread application, electric sensing systems have a number of disadvantages, such as loss of signal transmission, susceptibility to electromagnetic interference, the need to organize an intrinsically safe electrical circuit (if there is a danger of explosion). 

These inherent limitations make electrical sensors unsuitable or difficult to use for a number of tasks. The application of fiber optic sensing solutions is an excellent way to overcome these problems. The signal in fiber optic sensors is light in the optical fiber used instead of electricity in the copper wire of standard electrical sensors.

Over the past twenty years, a huge number of innovations in optoelectronics and in the field of fiber optic telecommunications have led to a significant reduction in the price of fiber sensor components and to a significant improvement in the quality of fiber optic systems. These improvements allow fiber optic sensors to move from the category of experimental laboratory devices to the category of widely used devices in such areas as monitoring of buildings and structures, etc.

One of the most commonly used fiber optic sensors is considered to be fiber Bragg grating sensors (FBG). The fiber Bragg gratings in these sensors reflect a light signal whose spectral characteristic (wavelength) shifts along with changes in the measured parameter (temperature and/or deformation). During the manufacture of gratings, a region with a periodic change in the refractive index is created inside the optical fiber core, herewith, this region is directly called the FBG.

Optical fibers and fiber sensors are non-conductive, electrically passive, and immune to EM interference. The interrogation using a tunable high-power laser allows measurements to be made over long distances with virtually no signal loss. Additionally, in contrast to the electrical sensing system, each optical fiber channel can interrogate a variety of FBG sensors, which significantly reduces the size and complexity of such a fiber optic system.

Fiber optic sensing solutions are ideal for applications where conventional electrical sensors (strain gauges, strings, thermoresistors, etc.) have proved difficult to use due to extreme conditions (long distances, EM fields, explosion protection, etc.). Since the installation and operation of fiber sensors are similar to conventional electrical sensors, it is easy to switch to fiber optic solutions. Understanding how such fiber optic systems work and the benefits of using them can greatly facilitate various measurement tasks (for example, structural health monitoring).

In short, the main advantages of FBG sensors include:

  • high sensitivity and performance;
  • relatively large range of measured deformations;
  • the best weight and overall dimensions, small size;
  • high noise immunity, insensitivity to electromagnetic interference, such as microwave field, spark discharge, magnetic fields, electromagnetic pulses of various nature and any intensity;
  • absolute electrical safety due to the absence of electrical circuits between the fiber optic sensor and the recording module;
  • full electrical, explosion and fire safety, high chemical resistance of sensor elements.

The conditions of the environment and controlled conditions in which one or more external factors — radiation, temperature, electromagnetic field, aggressiveness, humidity, pressure, and deformation — have the maximum possible constant values are regarded as extreme. 

In such conditions, primary converters of control systems for dangerous technological processes (oil production, transportation, and processing of oil and gas, nuclear power generation, storage of radioactive waste), monitoring and diagnostics systems for complex construction and engineering structures (dams, bridges, mines, etc.), and military and emergency management systems operate.

Currently, fiber optic technologies are widely used in various fields of science and technology. One of the main applications of fiber optics is the creation of portable high-sensitivity sensors. Pressure, strain, vibration, tilt, linear motion, and temperature sensors are widely applied in the industries of structural health monitoring pipelines, heating lines, power cables, mines, etc.

ajay-pal-singh-atwal-gRdTreyRops-unsplashRadiation

Compared to fiber sensors, the lack of power supply at the location of electrical sensing systems does not prevent continuous remote monitoring of dangerous objects, such as nuclear power plants, in an emergency beyond design situations. For instance, the well-known events at the Japanese nuclear power plant “Fukushima-1” in 2011 were characterized by the fact that during the two weeks when the nuclear power plant was completely de-energized, there was no information from electronic sensors, which was extremely important for monitoring the technical condition of the emergency station.

Temperature

Problems of standard sensing systems control of tightness of tanks with liquid hydrogen, which is the fuel of modern rocket engines, has a temperature of -253 °C and very high fluidity, due to the fact that at such temperatures, most materials become very fragile, and the sensitivity of palladium sensors quickly decreases. 

It is problematic to measure the pressure and dryness of superheated steam in gas generators and superheated gas in jet engine nozzles at temperatures up to + 600 °C since piezoelectric sensors quickly degrade at temperatures above + 300 °C. Modern FBG sensors of physical quantities are heat-resistant (up to +2300 °C) and cold-resistant (up to -270 °C). This provides reliable and long-term monitoring of the technical condition of high-temperature and cryogenic objects.

Electromagnetic interference

Measurements of physical quantities using electrical sensing systems in conditions of high-power electromagnetic interference, including guidance on coaxial electrical cables and sensors from lightning discharges, in conditions of monitoring the patient’s pulse in a medical nuclear magnetic resonance facility, as well as measurements of high voltages and high currents in electrical engineering, are highly problematic.

Fiber Bragg grating sensors are completely immune to electromagnetic interference and are stable insulators. This makes it possible to measure high voltages up to 800 kV and high currents up to 200 kA with high accuracy (class 02s) by fiber optic sensing technology.

Aggressive environment

Measurements of physical quantities of chemically aggressive media, long — term measurements of deformation of dynamically loaded objects and structures, as well as multi-sensor measurements-with the number of control points in several hundred and thousands, are also problematic for electrical sensing systems since the volume of measuring electrical cables is unacceptably increasing.

Distributed fiber optic sensors are multi-sensors: up to 10 thousand consecutive intra-fiber sensors can be used in one optical fiber (fiber optic cable) to measure physical quantities (temperature, strain, seismoacoustics, pressure, radiation, etc.). Multimode fiber optic cables allow performing remote measurements with high accuracy using borehole video cameras, and temperature fields — using pyrometers and thermal imagers.

Metrological calibration

A serious problem of electrical sensing systems embedded in objects (in the concrete of hydraulic dams and bridges, in the pylons and walls of high-rise buildings, etc.) presents the practical difficulty of their periodic calibration (metrological verification).

Modern fiber sensors have the function of metrological self-monitoring (FMSM) due to the multimodality of the optical signal, which allows for self-calibration of fiber optic sensors in real-time without stopping the controlled processes and without verification standards.

In the last decade, there were implemented many similar applications of modern fiber sensors and systems in extreme environments of nuclear, oil and gas and aerospace industries, shipbuilding, hydraulic engineering, energy, construction, military, and natural emergencies.

robin-sommer-wnOJ83k8r4w-unsplashMoreover, the durability of FBG sensors in these extreme conditions creates an obvious advantage of their use in the energy, oil and gas, aerospace, construction, and transport industries in comparison with non-optical types of measuring systems.

Thus, the extreme operating conditions of fiber Bragg grating sensors, for example in wells (extreme parameters, flammable, aggressive and abrasive environments) or power plants (ultra-high currents and discharges, voltages and fields, significant ionizing radiation), actually belong to the usual operating conditions of fiber optic sensors.

If you are looking for reliable fiber optic sensing solutions for structural health monitoring, you should choose the Optromix company. 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 

read more
editorFiber optic sensing solutions for extreme conditions

Fiber Bragg grating sensors perform structural health monitoring

on July 27, 2020

space-shuttle-774_640Nowadays fiber Bragg gratings are actively applied in the aerospace industry. The thing is that fiber optic multiplexing abilities of sensors based on FBG technology allow performing structural health monitoring of airborne vehicles resulting in an increase of their lifetime. Thus, fiber Bragg grating sensors play a crucial role in the spacecraft industry where mistakes and damage can lead to death.

It should be noted that fiber Bragg gratings are considered to be a thin optical fiber device that includes a physical “grating” area at its core. Herewith, the FBG core is not homogeneous, and the fiber optic sensor has a periodic variation in the refractive index of the material. Also, there is a dependency between the wavelength of light (reflected vs transmitted) and the periodic spacing of the grating.

FBG sensors can block specific wavelengths and transmit others like in laser cavities during the mode choice. Additionally, such factors as pressure and strain also influence the qualities of FBGs and the wavelengths resulting in stretching or compressing the grating period while temperature leads to thermo-optic effects. These and some other effects (for instance, vibration and displacement)  promote the application of fiber Bragg grating sensors to monitor various physical effects.

FBG sensors enable to determine ultrasonic and acoustic wave signals that are important in structural health monitoring of aerospace vehicles. For instance, acoustic-ultrasonic determination provided FBG technology helps to find out damage when the spacecraft is not mobile.

The detection offered by fiber optic sensors is regarded as highly accurate and quantitative because it is possible to monitor both the form function of the waves and the repetition of measurements. Nevertheless, the resolution and the bandwidth limitation of conventional tools employed with fiber Bragg gratings (for example, optical spectrum analyzers) do not enable accuracy in high-frequency determination.

The fact is that accurate determination of ultrasonic waves requires a demodulation method to interpret the detected signals. Four demodulation methods are distinguished in FBG technology both in practice and in laboratory testing: “a broadband light source (power detection), laser light source (edge-filter detection), Erbium-Doped Fiber Laser (EDFL), and modulated lasers.” Moreover, it is necessary to pay careful attention to the installation technique of the FBGs.

Finally, specialists apply several various techniques to employ fiber Bragg grating sensors into a vehicle or craft. The fiber optic sensors have been already tested at their installation into composite materials (inside of a fiber honeycomb sandwiches.) However, the technique can cause signal distortion, that is why an ideal way for spacecraft is gluing fiber Bragg gratings on with some adhesive.

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

read more
editorFiber Bragg grating sensors perform structural health monitoring

Fiber Bragg grating sensors measure physical factors

on July 6, 2020

tablet-2471184_640Fiber Bragg grating (FBG) has quickly become popular in fiber optics, and now it is impossible to imagine the absence of fiber optic sensing systems based on FBG technology. Researchers prefer to use fiber Bragg grating (FBG)-based sensing because of its benefits, for instance, compact size, fast response, distributed sensing, and immunity to the electromagnetic field. 

To be more precise, FBG technology finds its wide application in measurements of different physical factors (pressure, temperature, and strain for civil engineering, industrial engineering, military, maritime, and aerospace applications). Herewith, structural health monitoring of engineering and civil structures plays a crucial role now that can be easily carried out with fiber Bragg grating sensors.

It should be noted that the grating types of FBG include uniform, long, chirped, tilted, or phase-shifted (that has periodic perturbation of refractive index inside the core of the optical fiber). The development of fiber optic systems has greatly changed almost all areas of communication technology. Nowadays fiber optic sensors are widely used in the measurement of strain, refractive index, the vibration of structures and machines, electric current, voltage, impedance, temperature, pressure, humidity, etc.

Despite the crucial advancement in fiber optics,  integration of optical mirrors, partial reflector, and wavelength filters provide numerous difficulties because of the complexity and high cost of fiber optic systems. Nonetheless, FBG technology allows overcoming all these challenges because fiber Bragg grating can offer the function of reflection, dispersion, and filtering required for sensing applications.

Ever since its development, fiber Bragg grating sensors have obtained much attention because they offer numerous benefits, for example, pretty low cost, compact size, real-time response, high precision, high sensitivity, and independence to electromagnetic interference. Moreover, FBG sensors are considered to be very promising in measuring physical parameters.

Modern applications of fiber Bragg grating sensors include such areas as “high-temperature sensors, health and biomedical devices, structural engineering, industries, biochemical applications, radioactive environment, aerospace, maritime and civil engineering, and many other fields.” Additionally, FBG sensors rapidly moved from research laboratories to actual installation in fiber optic systems.

Finally, it is very difficult to think of fiber optic sensors without employing fiber Bragg gratings due to its attractive parameters, which make them a highly advanced technology in the sensing field. The combination of FBG technology with other systems, in turn, will lead to the overall enhancement of sensor design in terms of sensitivity, performance, cost, and size.

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

read more
editorFiber Bragg grating sensors measure physical factors

Fiber optic sensors began to be widely used in space

on June 29, 2020

nasa-yZygONrUBe8-unsplashMembers of NASA claim that they plan to test an enhanced fiber optic sensing system that allows performing thousands of measurements along the optical fiber about the thickness of a human hair for application in space. Herewith, such a promising fiber optic technology can control spacecraft systems during missions to the Moon and landings on Mars.

To be more precise, the system based on fiber optic sensors has been designed at NASA’s Armstrong Flight Research Center in California to obtain strain and other measurement data for aircraft. The researchers adapted the fiber optic system for application in space, where its potential uses contain temperature and strain information essential for space flight safety.

It should be noted that four fiber optic sensing systems are planned to test in space during five months, herewith, such tests carried out will demonstrate whether space fiber optic sensors can pass the hard conditions of a rocket launch. The thing is that rockets and spacecraft are considered to be highly complex systems and they have a myriad of various factors to be measured that is why NASA plans to keep the first applications of space fiber optic systems simple.

The new fiber optic technology based on space-rated sensors enables us to measure distributed temperatures on the Low-Earth Orbit Flight Test. The aim of aeroshell of the fiber optic system is to slow down and protect heavy payloads from the intense heat of atmospheric re-entry. Additionally, the fiber optic sensors monitor temperatures on the backside of the inflatable decelerator, therefore, the researchers “are working on space optical fiber experiment that will travel as a self-contained experiment on a Blue Origin New Shepard rocket through NASA’s Flight Opportunities program.”

The opportunities provided by fiber optic technology also include the decrease of the heat produced by the unit’s electronics and by way of conduction, or moving the heat away from the unit, because of a lack of air in space. The fiber optic system is regarded as self-contained and essentially ready for plug and play application. The thing is that the operating principle of the system is based on fiber optic sensors that can endure severe conditions to measure distributed temperatures in a cryogenic environment that play a crucial role.

NASA is also developing a compact, economically, and hardly fiber optic sensing system version. Thus, the new fiber optic technology based on a temperature-tuned laser is used to overcome the challenges. The researchers continue improving the production techniques of fiber optic sensors and discussing performing a potential test of the sensors at NASA’s Ames Research Center in California to support the study of the new fiber optic technology.

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

read more
editorFiber optic sensors began to be widely used in space