Fiber Bragg Grating Sensors for Weigh-in-Motion strips

Nowadays, road safety has advanced to a new level with the use of fiber Bragg grating sensors. Due to its characteristics, fiber optic technology has become part of the other technologies. For example, FBG sensors are applied in WIM systems (or Weigh-In-Motion systems) for that purpose.

There are several types of WIM systems and one of them is based on fiber Bragg grating sensors. Such systems provide specialists with the most accurate and detailed data around the clock, monitoring traffic flow. They are able to detect the vehicles and in the meantime determine their weight during the regular traffic. The traffic monitoring in real time allows improving the enhancement of traffic management.

Moreover, fiber Bragg gratings (FBGs) are used in WIM systems for the structural health monitoring, for example, of the bridges or rails.FBG Sensors for Weigh-in-Motion strips

What is Weigh-in-Motion (WIM) Technology?

Weigh-in-motion (WIM) systems are based on technology that allows providing reliable weight measurements of the vehicles. The systems can be applied whether for specific road or rail vehicles such as trucks and trains, or for public applications like be set on the rail or road tracks to monitor the traffic. Weigh-in-motion systems built on fiber Bragg grating sensors measure the traffic flow and supply all the information from it. Thanks to the durability and quality of FBG sensors, the necessary data is provided using one of the most cost-effective methods.

The whole fiber optic system consists of a range of sensors and a roadside unit with all the data devices. According to the application purposes, there is an opportunity to add other fiber optic sensors to this weigh-in-motion system, for instance, temperature sensors. Moreover, to receive more data about the vehicles, it is possible to use cameras for license plate photos.

What Information do the Weigh-in-Motion Systems Provide?

Fiber optic sensors follow two basic physical principles. The first principle that belongs to fiber Bragg gratings is the diffraction changes under the deformations. The second one is the changes of the optical fibers and their characteristics under the influence of the deformation. Therefore, the WIM systems provide all the characteristics that fiber optic technology offers.

The reliable data on weight from fiber optic sensors give an understanding of the loading of heavy goods vehicles and traffic flow. FBG sensors will help in estimation, avoiding any inaccuracy in the future. This, in turn, will allow improving the goods transportation and infrastructure management.

Except for the usual weight parameters that fiber optic systems provide, there are other available options, such as date-time, speed and classes of vehicles. To efficiently operate, the fiber optic systems can be installed on the specific vehicle or placed by the road for the entire traffic flow monitoring.

Advantages and Disadvantages of the Fiber Optic Sensors

As any technology based on fiber optic sensors, WIM systems possess all the features that FBG sensors have. Such characteristics as light weight, small size and insensitivity to the electromagnetic fields and weather conditions are really important in monitoring systems. Moreover, WIM systems have an ability to identify the underinflated or double tires in the traffic stream.

Weigh-in-motion systems help in providing very short response time in operations. However, there is a possibility of some inaccuracy of weighting, especially in motion. That’s why specialists are aiming at enhancing the same level of accuracy in motion as in static. And sometimes there is no use in enhancing the fiber Bragg grating sensors’ accuracy level, but increasing the number of sensors or making the automatic calibration processes better. There is a range of external factors that influence fiber optic sensors’ operation such as vehicle suspension, road roughness, etc. Moreover, they can influence the accuracy level in a bad way.

The most commonly agreed disadvantage is relatively high cost for electronic equipment. However, due to the long service life of fiber optic sensors, WIM systems seem to be a cost-effective technique by operating for at least 10 years.

Applications of the Weigh-in-Motion Systems

Fiber optic solutions are applied for many purposes as WIM systems. If it is needed, WIM unit can provide several data parameters at once. Usually, such data is applied in the following spheres:

  • Vehicle and traffic loading. As it was mentioned before, the information on the traffic flow helps in optimization and planning of the road network in the future. Or the researchers frequently apply it for carrying out the studies. However, there is another implementation that can be used for the already existing infrastructure – for example, for the review of the traffic flow over the road network and its future development with time.
  • Weight enforcement is aimed at complying with loading regulations. This will lead to the decline of the overloading numbers that have negative implications. These WIM systems based on the FBG principles provide the most effective instrument of weight enforcement.
  • WIM systems based on the FBGs can also be applied for industrial use like in logistic centers or at ports. They are most commonly needed in the weight check and defining of the trucks’ axle loads. All these measures are aimed at avoiding overloads and their possible future consequences of entering the road network.
  • WIM systems with fiber optic sensors for the railway industry are as well effective as DAS systems described in previous articles. The most common ways of application in this sphere are the total track loading and dynamic wheel loads. In practical terms, the provided data helps in design and maintenance of the rail tracks.

In the future WIM systems with fiber optic sensors will allow creating one of the base elements of the “Smart City” concept. The FBG sensors are able to provide the system that with different types of sensors will form a complex and reliable technology. Moreover, the improvement of the weigh-in-motion systems based on the fiber Bragg grating sensors will lead to the decrease of overloaded trucks on roads.

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

Fiber Optic Sensor (FOS) Technology and its Applications

Thanks to all the advantages of the fiber optic sensor (FOS) technology and its diversity of instruments, described in the previous article, there are a range of applications. Structural health monitoring of the concrete constructions is proved to be the most effective tool for management of the infrastructure, due to the latest results.FOS Technology and its Applications

Here is a list of the most common applications where fiber Bragg grating sensors can be installed.


The lifetime of every large bridge is several decades or hundreds of years, including the period of construction and repair stages. Despite the improved quality of the bridges’ planning, it is still difficult to accurately predict its lifetime because of the complex structures and external influence like corrosion or the natural disasters like earthquake, flood, etc.

The structural health monitoring in real time gives an insurance of the safety of bridges. According to the researchers, this fiber optic system can be applied on the different stages of the bridge construction. Most of all, these fiber optic monitoring systems are used in the operation or safety phase of bridges and extend their lifespan.

The FBG structural health monitoring systems include fiber optic sensors, multiplexers, FBG interrogators, local and remote computers.

All in all, the fiber optic monitoring systems provide the following advantages:

  • Control of state of metal structures;
  • Control of the bridge oscillation frequency;
  • Notifications for the personnel on screen;
  • Extending the bridge’s lifetime, etc.

Moreover, when we talk about the railroad bridges, it is also possible to evaluate the lower bridge beam condition.


The state of the load-bearing structure and building foundation is a crucial element of safety. And fiber optic sensors have made a great contribution to it.

The structural health monitoring can be applied whether for the buildings under construction or for the old houses when there is a severe level of damage and degradation of materials. Unfortunately, the majority of the houses that were built before, mostly in the previous century, are particularly vulnerable to environmental actions. Basically, because there was no specific constructive detailing that would provide the age resistance of the constructions.

The degradation usually includes steel corrosion, debonding of concrete, etc. It becomes visible when the damage is greatly extended on the elements of the structure. If the moment for the structural repair is missed, it often leads to its more complex and expensive modernization. At worst, there is a need for demolition.

Mostly, fiber optic technology is used for:

  • Control of the strain-stress state of metal basic structures and foundations;
  • Monitoring of the cracks and foundation shrinkage in reinforced concrete structures;
  • Snow load control.


The structural health monitoring systems have also made a great contribution into tunnel construction.

The most important safety factor in tunnels, as in many civil structures, is the deformations. Fiber optic sensors can monitor and provide the useful data both within the construction phases and over the long term. In the long term, monitoring calls a very stable and precise system that can compare deformation measurements over long periods. In the short term, the monitoring system can measure deformations that occur for relatively short periods.

The structural health monitoring system influences the tunnels’ management and security by providing in-time maintenance and restoration. There is a problem of excessive deformations which can seldom affect the structural security, but can cause durability problems.

For example, such fiber optic monitoring systems can be applied during the highway tunnel’ construction to measure the tunnel load or to monitor railway tunnels. Besides, the knowledge of the tunnel’s behavior helps while the introduction of the modern building techniques or for the prolongation of its service life in the future.

Hydroelectric and Wind Power Plants

Fiber optic solutions have found their applications for nuclear, hydroelectric, wind power plants. Aging management of the components is directly related to their operation. Safety requirements guarantee their safe operation but still are difficult for operators to track fully. All kinds of power plants require the accurate and qualified assessment of the thermomechanical loads and other parameters that can lead to the early aging of the equipment.

Fiber optic sensing is one of the best monitoring and maintaining systems for the plants. Structural health monitoring (SHM) of hydroelectric plants, wind turbines and others gives operators real-time information of the components’ condition.


As for the dams, fiber optic technology helps in detection of the seepage flow changes in a dam structure. Dams usually face different problems connected to external loads such as water level changes, seismic disturbances, etc. Any changes in numbers can be a sign of erosion which is the most common cause of the dam failure.

Fiber optic system allows operators to get the data from all over the dam as measurements are taken along the full length of the cable. Distributed sensing detects the tiniest changes in rates that otherwise can lead to the operational failures.

Fiber optic sensors are able to measure various parameters and quantities in structural health monitoring. Depending on the required operating principles, specialists discuss which type of FBG sensor is the best suitable and their way of embedding and surface mounting. All in all, their final goal is to find the most effective fiber optic solution for the operating principle and potential applications in SHM.

The short list of applications can be also found on our website.

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

Fiber Bragg Grating Sensors for Railways

Fiber Bragg grating (FBG) sensors have already been applied in various applications and still arouse great production interest. They are commonly used in structural health monitoring for aerospace, civil engineering, oil & gas, etc.

As for the railway industry, fiber optic technology has made a substantial contribution to its development. It is anticipated that within a few years the number of goods that will be transported by railways will be increased, as well as the number of passengers. This, in turn, will lead to the growth of the axle load and trains’ faster speeds operating.

That’s why there is a great need for a full understanding of the rails’ structural and operating conditions as well as for providing safe and reliable operating conditions. So modern innovative technologies are required.

FBG Sensors for Railways

Fiber Optic Solutions for Monitoring Systems in the Railway Industry

In railways, common monitoring systems use strain gauge sensors. The sensors constantly measure resistance caused by the stress transmitted by the rail when the train runs through it. This fiber optic technology is already prominent due to its effectiveness. However, it still has several shortcomings. For example, it is expensive, huge and has difficulties in usage, in comparison with modern FBG sensors. Moreover, the most important disadvantage is that they can be affected by electromagnetic interference. FBG sensors are immune to the external interference such as electromagnetic interference, lightning and many other external disturbances.

Because of this, fiber Bragg grating sensors are getting more and more applications in high-speed railway networks. Applications are train weight estimation, measurement of train speed for real time, wheel imbalance detection, etc. It is clear from experiments that FBG sensors are more appropriate as railway monitoring systems compared to electrical ones.

Fiber Bragg Grating Sensors Characteristics

FBG sensors provide many crucial features for unique operational conditions in railways. In comparison with usual electrical sensors, fiber Bragg grating sensors have EMI/RFI immunity, multiplexing capability and can offer interrogation for long distances. In FBGs the data is wavelength-encoded, which makes the signals less susceptible to intensity fluctuations. Moreover, the fiber optic cable can be interrogated from either end, offering redundancy to FBG sensing networks. Plus, FBGs have a self-calibration capability. The strain and temperature measured findings is an absolute parameter. So there is no dependency on the measurement value and losses between the interrogation unit and the FBGs. To fabricate FBG sensors, FBGs are packaged and transformed into different types of transducers. That makes it possible to install them on the rail track fasteners, clips, bogie, train body, chassis, and axle boxes of a train to provide ongoing inspection for health checking.

In addition to that, FBG sensors can be interrogated at very high-speeds.

Providing reliable operational conditions, fiber optic designs can measure a wide range of other parameters such as inclination and acceleration through the modulation of light in reaction to the environment. Therefore, one FBG interrogator can work with a lot of FBG sensors to measure many options at the same time at different locations over the vast territory. The sensing signals can be read at distances more than 100 km away.

These features are especially useful for the railway industry because they allow simplifying the installations a lot and reducing costs.

Fiber Bragg Grating Sensors in Field Projects

Over the past few years, specialists have safely held a number of field trial railway projects involving FBG sensors. For example, in 2007, about fifty FBG-based vibration sensors were installed along the East Rail Link that connects Hong Kong and Mainland China. Then fiber optic solutions were applied in metro lines of Hong Kong, part of the Beijing-Shanghai High-speed Rail Link, and in Delhi Airport Metro Express Line.

In Hong Kong this fiber optic technology was applied on a passenger rail system as a structural health monitoring system. The FBG sensors were attached to the bottom of the carriages. The goal was temperature and strain measurement. The fiber optic system supplied all the necessary data including rail tracks’ and carriages’ deformation. The acquired information helped to assess the rates of the corrosion and bearing wear.

According to the results, due to FBG sensors, costs of maintenance were greatly reduced. Moreover, it helped to avoid or prevent problems at early stages due to the early detection of excessive vibrations. All these works showed that FBG sensors are superior in comparison with conventional sensors in many essential aspects.

Nowadays, fiber optic solutions are regarded as one the most cost-effective technology that helps in monitoring the condition and structural health of the carriages, tracks, and under frame equipment in railway systems. There are still some parameters that need to be improved, like the lack of proprietary and custom specifications. However, in the future major railway operators can apply modern FBG sensors, gaining more field experience.

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

Fiber Optic Sensing for the Steam Assisted Gravity Drainage

Fiber optic sensing technology has proved to be an effective method in well and reservoir management. Fiber optic sensors constantly track temperature changes along the wells at specified intervals and collect all the data.
This technique is also compliant with the other technologies such as Steam Assisted Gravity Drainage (SAGD).

What is Steam Assisted Gravity Drainage?

Steam Assisted Gravity Drainage (or SAGD) is an enhanced oil recovery drilling technique that helps in extracting heavy crude oil or bitumen from oil sands deposits. Mostly, the accustomed approaches in such cases are economically inefficient. Specialists may use it in particular cases when the production is difficult. With the help of the fiber optic technology this approach becomes more cost-effective.

Fiber Optic Sensing for the Steam Assisted Gravity Drainage (SAGD)

How does Steam Assisted Gravity Drainage work?

In short, the SAGD system’s principle is heating the heavy oil or bitumen by the steam for further extraction. For that two horizontal wells are drilled at an angle of 90 degrees to a vertical bore well. In the wells, there are two pipes, one above the other for around 4-5 meters.

At the very beginning, the cold heavy oil is essentially immobile because of the high viscosity, and it needs to be warmed up to extract it. To do so, the steam is applied. It travels through the upper well into the reservoir and expends the heat in all directions of the formation, making a steam chamber. The heat warms the bitumen and reduces its viscosity. Then the bitumen flows downward into the production well and is pumped to the surface. Both processes are going at the same time.

Current Applications of the Steam Assisted Gravity Drainage

Due to the growing level of oil consumption, the level of its development needs to be increased. Not the last role is played by the SAGD and fiber optic systems such as fiber optic sensors and fiber Bragg gratings.

Like any exploration, heavy oil production needs accurate analysis and planning, especially if there are other factors that make the production difficult. Such aspects as great depth, high temperature conditions, etc. are essential. All of these issues need to be considered. The low mobility and high viscosity make the oil producing complicated and lead to low recovery indexes. However, due to the SAGD and fiber optic technology, there is an opportunity to maximize the recovery indexes.

For SAGD technology, FBG sensors are usually applied in wells to track the steam as it moves along the wellbore. Due to the fiber optic sensors, there is an opportunity to see the data in real time. According to the achieved data, the velocity of the steam can be identified. Besides, temperature sensors can also define the speed of the heating. The accurate settings of the temperature, pressure and steam-injection rates can lead to the operational savings. All the information can be used to plan the further work of the production operations.

Fiber Optic Sensors in Downhole Monitoring

Fiber optic sensors have proved to be effective for various parameters’ monitoring in downhole applications. Most of all, distributed temperature sensing (DTS) is applied for these purposes. Distributed sensing has demonstrated good results. It has high recommendations in the oil industry. DTS can monitor well temperature all over the fiber optic cable.

Due to the modernly developed fiber optic designs and improvement of fiber optic sensing technology, a range of issues related to downhole production have been solved. However, the harsh environmental conditions in the downhole can still bring some problems to the fiber optic sensors.

The sensors still need to cope with hydrogen in the severe environmental conditions. It has a great impact on the optical fibers. Firstly, it can cause pressure and temperature errors. The appearing errors are connected to the hydrogen diffusion into the microstructure and to the changes of the refractive index when hydrogen penetrates into micro holes and fiberglass. So the hydrogen leads to the additional Bragg wavelength shift.

With this in mind, specialists are constantly developing fiber optic monitoring systems based on fiber Bragg grating technology.

Advantages and disadvantages of the SAGD

SAGD has played a crucial role in the rapid development of the oil resources. However, as everything, this method has some pros and cons that should be taken into account.

Most Common Disadvantages for SAGD technology

  • Firstly, as any other technology, SAGD has its restrictions. It is not well-suited for every production area with heavy oil. It has several aspects to be fulfilled, like homogeneous and relatively thick reservoirs.
  • Secondly, high water and fuel consumption. To work effectively, SAGD needs a large amount of water and natural gas. Both of them are used in the process of steam production. That’s why the energy consumption is high but worth it. When all these conditions are satisfied, SAGD technology can be used. Moreover, the specialists advise using deep water sources that are not appropriate for consumption or agricultural uses. In fact, the majority of deployments’ developers follow this recommendation for environmental protection.
  • Thirdly, some think that SAGD technology is an expensive tool for oil production. However, specialists consider this technology as a superior alternative to reduce the high expenses and at the same time increase productivity. The reason for the cost reduction is that less horizontal wells are required to be drilled.
  • Fourthly, concerns about an environmental effect of the steam assisted gravity drainage (SAGD) are still a topic of discussion. However, according to the statistics, over the last 20 years the environmental analysis is getting better. It is obvious that the production of the crude bitumen and oil cause environmental consequences, but due to the development of modern cleaner extraction technologies, the situation is improving.

The Main Advantages of the SAGD technology

The main benefit of the whole SAGD technology is the improved steam-oil ratio and high ultimate recovery. Besides, the DTS systems help in optimization of the oil and bitumen production.

The other SAGD advantage is the constant evolution. Every next project makes a great contribution and brings new ideas and experiences. Meanwhile, the diversity of newly developed methods leads to new approaches to different types of oil fields.

So there are other modified types of SAGD technique:

  • Shaft and Tunnel Access (SATAC);
  • Single Well SAGD (SW-SAGD);
  • Multi-drain SAGD;
  • Fast-SAGD;
  • Enhanced Steam Assisted Gravity Drainage (ESAGD).

The SAGD was firstly implemented in Canada, where there are the largest reservoirs of crude bitumen. This allowed to advance the recovery factors in excess of 50%.

SAGD (steam assisted gravity drainage) well temperature monitoring provide:

  • Temperature profile control of injection and production wells;
  • Determination of inflow (injection) intervals of the fluid;
  • Determination of the fluid level in the well and perforation intervals;
  • Identification of issues in the well.

Plus, as any fiber optic technology, distributed temperature sensing for SAGD offers:

  • Maximum protection of the cable against chemical and physical effects;
  • Longer service life;
  • Convenience and speed of the installation;
  • Operations in the well without the extraction of the cable sensor.

The SAGD wells have implemented all the advantages of fiber optic sensing. FBG sensors offer real-time, precise temperature measurements along the fiber optic cable in the wellbore. Fiber optic solutions allowed us to monitor the objects that were unapproachable before. For example, fiber optic sensors with extended temperature range were applied in the oil wells for temperature control during oil production using SAGD technology.

Steam assisted gravity drainage is commonly believed to be applied for complex deployments. It aims to make the process simpler. And the fiber optic technology is good at helping it. However, the specialists should discuss and decide how fiber optic technology can fit into the development at the planning stage. Fiber optic solutions may simplify the production process.

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

Fiber Optic Sensors for the Structural Health Monitoring

Structural health monitoring or SHM is a crucial technique thanks to the development of architectural design. Its main goal is ensuring safety for the civil infrastructure. Due to the fiber optic sensors‘ benefits, a great number of the distributed sensing systems have found application in civil engineering as SHM systems.Fiber Optic Sensors for SHM systems

What is a Structural Health Monitoring System?

Structural health monitoring is a technique of evaluating and monitoring structural health. Thanks to its capability to respond to unfavorable changes, this method is widely used in many fields including aerospace, civil, and energy sectors, etc.

Why is SHM necessary?

All structures are vulnerable to various internal and external factors that can lead to wear or malfunction. There are various reasons that can cause it. For instance, deterioration, problems in construction process, an accident or environmental load, etc. That’s why it is important to implement a monitoring system.

Damage identification systems monitor all the changes in rates in real time 24/7. It gives an opportunity to detect deviations quickly and react properly in a short period of time before significant damage is caused. Therefore, timely maintenance and repair actions reduce the repair time and operating costs.

The structural health monitoring systems provide the following benefits:

  • Increased security;
  • Detecting of the damages at an early stage of difficulties;
  • Continuous tracking;
  • Saving of operating costs and time;
  • Development of rational management and maintenance strategies, etc.

Typical Fiber Optic Sensors

In accordance with the increase of the number of buildings’ and bridges’ under construction, the health monitoring of the concrete structures has become a topical issue.

1. Temperature Sensors

Most of all, the health of the concrete structure depends on the temperature influence. Its monitoring influences the general quality and thermal resistance of the entire structure.

At early stages, the temperature shifts affect structure’ cracks and thermal stresses that are usually caused by hydration. Besides, with the help of the two crucial parameters, the maximum temperature and the temperature trend, specialists predict the future structural health.

In addition to that, there is a special system called Distributed Temperature Sensing (DTS) that helps to monitor the cracks that may appear in the concrete structures. Its low cost and well-considered technology are believed to be important advantages in measurement. Other advantages of the FBG temperature sensors are their accurate measurements and fast response. Besides, temperature sensors are perfect for hard-to-reach places and massive sensing networks.

2. Strain Sensors

Another popular type of the fiber optic sensors is FBG strain sensors. To find out the deformation degree, the structure’s density information is used. In fact, the stability of the structure depends on its strength. It is safe when the structure strength is greater than the applied pressure.

After calibration, the unit acquires the features of a force transducer. The strain sensor transfers the component strain accurately. Characteristics such as light phase, frequency, amplitude, or polarization state, allow operators to monitor the health of the structure. All these features change under the influence of deformation.

Due to the common features of the strain sensors, like small size, they are universal sensors for force and load control. They are often used in large machines and steel constructions where there are high loads.

3. Displacement sensors

The other type of sensors are displacement sensors the main task of which is displacement measurement. It becomes possible by the constant measurement of the distance between the sensor and an object.

These FBG sensors are frequently used because they are greatly resistant to external impacts like corrosion and electromagnetic interference. Moreover, they are applied where long term reliability and safety are demanded.

If we compare them to the strain sensors and temperature sensors, FBG displacement sensors can’t measure quantity using only fiber optic sensors. They utilize FBG response to its equivalent Bragg wavelength.

Displacement sensors are perfect for monitoring of the civil engineering structures 24/7. They are suitable for monitoring aircraft, concrete structures and other industrial applications.

4. Pressure sensors

FBG pressure sensors use reflected wavelength analysis. This kind of sensors measure various parameters under severe conditions like high temperature or pressure rates.

The fiber pressure sensor’ operational principle is based on the fact that external factors affect the Bragg wavelengths by influencing the pressure sensor. In such a case, changes of the FBG’s physical or geometrical properties are implicitly measured.

FBG pressure sensors have the same characteristics as the other fiber optic sensors. They are small, portable and provide the highest accuracy and stability.

Usually, fiber pressure sensors measure the levels of liquids and gas in pipelines or tanks. They are used for the indirect flow control in tanks and pipes. FBG pressure sensors are crucially essential in various industrial fields like liquid level monitoring in oil storage tanks, gas turbine engines, etc.

In conclusion, we should say that any of these fiber optic sensors can perform measurements as a structural health monitoring. According to the existing situation and characteristics, the specialists choose the suitable variant, thus ensuring safety for any kind of civil construction.

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

Fiber Bragg grating sensors for overhead transmission lines’ monitoring

Fiber Bragg grating sensors have a wide range of applications starting from the oil & gas industry and ending with structural health monitoring. However, few people know that FBG sensors are also effectively used to prevent icing on the overhead transmission lines.

According to the statistics, many countries have already faced great accidents and vast economic loss caused by the icing on the overhead transmission lines. The frequent icing load can lead to catastrophic consequences, for example, line breaks, short circuits, and tower collapses. In such disasters, thousands of people find themselves without electricity.

FBG sensors for overhead transmission lines’ monitoring

Fiber optic sensors VS electric ones in icing monitoring

Nowadays, there are different technologies for icing monitoring that can be produced both for individual transmission lines and for the whole energy transport infrastructure. The common ways of icing conditions estimation are dip-sag monitoring, video surveillance, non-contact infrared measurement, etc. All these methods usually can’t give accurate data on icing thickness, and they have got difficulties because of electromagnetic interference with the power supply.

Compared to the traditional sensors, fiber optic sensors improve the effectiveness of accident prevention through monitoring and control with the help of automated instruments and systems.

The main system’s features in icing monitoring are:

  • The system monitors the onset of icing in accordance with changes in the load and sag of the span.
  • The system includes an ice melting system.
  • The system monitors the temperature of the ground wire and switches the melting off automatically.

FBG sensors’ main advantages for icing monitoring

In fact, fiber Bragg grating (FBG) sensors have already turned out to be an excellent solution for solving all the issues where electric sensors failed. In comparison with them, fiber optic sensors apply light for change monitoring in strain, temperature, and other parameters. It means that their accuracy doesn’t depend on electromagnetic interference.

Over recent years, FBG sensors have proved to have a lot of potential in monitoring the transmission lines. Fiber Bragg grating (FBG) sensors’ advantages are:

  • compact size,
  • lightweight,
  • tolerance to corrosion and to electromagnetic interference,
  • resistance to the environmental impact,
  • high-temperature stability,
  • explosion and fire safety,
  • wide range of measurements, etc.

Scientists made FBG sensors able to define the accurate phase without a special reference point. Moreover, they can also suit for grid monitoring and distributed measurement.

Thanks to modern measurement methods such as distributed fiber optic sensors, a complex problem of monitoring the start of the ice formation can be solved, and there is the most effective way to eliminate it.

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

FBG sensors for Structural Health Monitoring

Structural health monitoring (SHM) is considered to be one of the most effective modern fiber optic technologies. Its aim is to provide robust information about engineering structures’ integrity and safety. Thanks to it, specialists can indicate the need for repair or retirement in advance and eliminate problems. Such a system of structural condition monitoring is based on fiber Bragg grating sensors.

FBG sensors for Structural Health Monitoring

Fiber Bragg Grating (FBG) sensors as a part of structural health monitoring systems

FBG sensors have proved to be reliable monitoring instruments. Thanks to the variety of FBG sensors, they have a great advantage in comparison with other technologies.

The main types of Fiber Bragg Grating sensors:

  • Temperature sensors;
  • Strain sensors;
  • Displacement sensors;
  • Pressure sensors, etc.

Newly developed FBG sensors are widely applied to measure and register static values in various industries. Scientists have discovered their abilities in ultrasonic detection and capacity for ultrasonic structural health monitoring. To provide the accuracy of the results, ultrasonic detection needs a broad bandwidth and high sensitivity. That’s why Fiber Bragg Grating (FBG) sensors need to be properly designed, taking into account data process and installation methods.

Main steps for structural health monitoring implementation

SHM allows the predictive maintenance of engineering structures and machines. There is no need in turning the whole system off because structural health monitoring can detect damages while operating. Mechanisms can keep working over a long period of time.

There are three main steps for SHM implementation:

  • Finding the most suitable locations for FBG sensors. It means the modeling of the most probable simulation. Engineers identify critical areas where it is better to install sensors.
  • Data gathering. At this step, FBG sensors monitor the health of the structures in normal and maximum loading conditions. They need to know the usual numbers for loading conditions to see any differences in the future. The received data also allows conducting a statistical study to determine the normal functionality of the engineering structures.
  • Comparison of the received data and standard behavior rates. Special algorithm(s) allows comparison even without extra manpower. If the values obtained don’t match the predetermined level, the software defines whether there is a possibility of structural failure. If ‘yes’, then the program informs about problems that have arisen with warnings and alarms.

The areas in which structural health monitoring systems are most commonly used, for example, are the gas and oil industry. In addition, recently this technology has been applied on a fish farm. Specialists have designed a customized structural health monitoring system that allows them to see the whole picture of fish farming’s biological and technological aspects. Fiber optic technology still has a wide range of industries to develop.

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

Fiber Bragg Grating (FBG) sensors for railway monitoring

For the last decade, fiber Bragg grating (FBG) sensors have been attracting more attention from scientists all over the globe thanks to their numeral benefits. Nowadays, they are widely applied in health monitoring, aerospace, civil engineering, oil & gas, smart structures, etc. In this article, we will consider FBG sensors for one of the most used transportation systems, for railways.

FBG sensors in railway transport systems

Railway transport systems have faced a range of difficulties such as longer service availability, providing high safety levels, reduced energy consumption, and optimal operation. Monitoring systems should meet all of these tasks without interruption.

According to many successful pieces of research, fiber optic technology can provide all these aspects at once, it can be applied to ensure railway monitoring. It is important to understand the structural and operating conditions of rails and freight and passenger service cars to provide safe and reliable work.

FBG sensors for railway monitoring

The point is that FBG sensors have many crucial characteristics that perfectly suit railways’ operational conditions. For instance, it is a very long-range interrogation, that is better, especially in comparison with usual electrical sensors. Fiber Bragg Grating sensors are the only sensors that measure all the data and offer it in real-time. FBGs also are low susceptible to fluctuations. Moreover, they can be interrogated from any end.

All these features are especially significant for the railways in providing safe operations. In addition to that, FBGs are universal and can be applied for measuring many other parameters like inclination and acceleration over a large area.

Recent programs with fiber Bragg grating sensors

The most recent project where Fiber Bragg Grating sensors are involved is taken place in India. The main goal is to make the railways there safer with the help of fiber optic technology. Specialists have used sensing technology to reduce travel time and increase the trains’ speed between two states. The railway construction will be conducted by a developed structural health monitoring system.

Thanks to monitoring systems based on fiber optic solutions, rail corporations could easily get real-time data about rail structures’ conditions within 24 hours. Therefore, this feature will fast the warning alerts for possible damage detection. The fiber optic technology can be configured for any type of location and structure, even in vulnerable areas. It is specially referred to as earth slip locations, heavy rainfall areas, etc. However, recently only routine manual inspection is carried out in such cases. Constant monitoring with the FBG sensors will provide real rail safety in such areas.

The government considers that the potential of fiber Bragg grating (FBG) sensors is huge and can be applied in other projects on rail safety. It allows finding the structural defects out as early as possible, not only when an accident occurs. The preventative work gives an opportunity to avoid many troubles and mass casualties that happen.
All in all, thanks to constant real-time monitoring, timely warning alerts, and the possibility of applying in severe environmental circumstances, specialists can use fiber optic technology in many spheres, as well as railways.

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

Fiber Bragg Grating (FBG) Sensors for Industrial Sensing

Recently, researchers have presented a new generation of fiber Bragg grating (FBG) sensors that are covered with aluminum and copper. These FBG sensors are compact and hermetically sealed. Depending on the applied coating, they are resistant to high or low temperatures and can be applied in harsh environmental conditions. As well as gold-coated fiber Bragg grating sensors, they are representatives of a modern generation of humidity-proof different sensors, for example, temperature sensors, strain sensors, pressure sensors, etc.

Main Fiber Bragg Grating Sensors advantages

It’s a well-known fact that FBG sensors are widely applied in various fields and spheres thanks to their advantages. A lot of measurements in harsh environmental conditions would become possible by the usage of fiber optic technology.

Here are the most common advantages of fiber Bragg grating sensors:

  • absolute temperature and other measurements in comparison with usual electric sensors;
  • rapid linear response in strain, pressure, or temperature measurements;
  • the compact size of the construction reduces the weight and allows to use of many sensing points on a single fiber strand;
  • measurements over long distances;
  • acceptable price, etc.

FBG Sensors for Industrial Sensing


The new type of FBG Sensors

However, a usual FBG sensor with the glass fiber coating can have several limitations because of the high humidity, high temperatures, corrosion, etc. The new type of Fiber Bragg Gratings are embedded into optical fibers coated with aluminum, copper, or gold have much more applications.

Scientists have offered processes that allow providing two lays of metal coatings. It gives an opportunity to create different lengths of window stripping and make the second layer with the needed thickness and length.

In conclusion, we must say that scientists from all over the world keep finding new fiber optic solutions to solve the modern problems we face in real life. That means that fiber optic technology will be better and more effective every day.

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

Fiber Optic Sensors’ development as wearable

Over the last few decades, scientists could achieve considerable progress in creating wearable sensors. Wearable sensors are newly developed inventions that can detect physiological and biochemical markers for health monitoring. Fiber optic solutions such as fiber optic sensors were no exception and made a great contribution to this technology.

What are wearable sensors?

Wearable sensors have an enormous potential for the early detection of many diseases including Covid-19 by measuring numerous vital signs such as blood oxygen level, respiratory rate, etc. According to the studies on Covid-19, the most common symptoms are shortness of breath, fever, and fatigue. Moreover, the blood oxygen level of an infected patient is lower because it is a respiratory disease. That’s why it was important to create a fiber optic technology capable of providing accurate data that would be useful for specialists and non-specialists alike people in quarantine or self-isolated.

Wearable Fiber Optic Sensors

Fiber optic sensors for medicine

Fiber optic sensors have attracted attention by development as flexible sensors. They usually consist of optical gratings and optical fibers embedded into polymeric matrices. For example, wearable systems based on fiber Bragg grating (FBG) were developed for biomedical usage. Thanks to their small size, lightweight, and other advantages, they can be easily integrated into polymers or textiles.

FBGs were suggested as wearable sensors for respiratory measurement for the upper body like abdomen and chest movements. FBG output changes can show the respiratory rate and breathing pattern. Moreover, with the help of fiber optic sensors, specialists are able to receive information about cardiac activities. The suggested fiber optic system has high sensitivity and can respond to environmental factors, for instance, relative humidity, temperature, and water immersion. Researchers noticed that the temperature had more influence on them in comparison with water immersion and humidity. That means that this fiber optic system needs further investigation.

The new humidity sensors were also developed based on optical fibers. The humidity also influences the light intensity of the emitted light of optical fibers. This function was used for developing a fiber optic system to measure the level of the nasal exhaled breath for respiratory rate tracking. In this system, scientists have placed a Fiber Bragg grating in an agar substrate. This device with fiber optic sensors demonstrated reliable performance and nice sensitivity to relative humidity change.

Thanks to the newly designed wearable fiber optic sensors, it became possible to integrate the health data of each person and find the best option for him.

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