Tag: FBGs

Optical fiber temperature sensors and their applications

FBG temperature sensors FBG sensors give the opportunity to measure a variety of parameters in conditions where other sensor technologies fail or simply cannot operate. Such FBG sensors have intrinsic advantages, including resistance to electromagnetic interference, non-electrical conductivity, passive measurements, small size and small weight, and the option of multipoint measurements. the reflection wavelength of the FBG (Bragg wavelength) depends on the grating characteristics (period, modulation) and is influenced by the ambient conditions such as strain and temperature. The development of fiber optic devices based on fiber optic sensors for operation in harsh environments (such as for temperatures of up to 1000°С) is becoming an increasingly important field. In the case of temperature sensing the Bragg wavelength is a function of the temperature. This temperature dependence results from changes in the refractive index of the fiber as well as from thermal expansion of the glass material. Many material properties show strong temperature dependence. Examples of such temperature dependencies are dew point, density, electrical conductivity, refractive index, rigidity, and diffusion. Temperature measurement also plays an important role in the health monitoring of electric circuits or civil structures.

The main advantages of FBG sensors are their measurement of reflected light, wavelength-encoded sensing, and multiplexing capability. Nowadays there are many types of FBG sensors used for measuring temperature: intrinsic and extrinsic.

Three major types exist:

The intensity-modulated sensors

Intensity-modulated FBG sensors are based on the principle of letting a physical disturbance such as temperature cause a change in the received light through an optical fiber;

The phase-modulated sensors

The phase-modulated FBG sensors are based on the principle of comparing the phase of light in the sensing fiber with a reference fiber in an interferometer;

The wavelength modulated sensors

Wavelength modulated FBG sensors are based on the principle that a physical disturbance such as temperature or strain changes the reflected wavelength of the light.

In general, it should be noted, phase modulated and wave modulated FBG sensors are providing much more accurate measurements than intensity-modulated sensors but at the cost of much more expensive interrogators.

Optromix, Inc. is a U.S. manufacturer of innovative fiber optic products for the global market, based in Cambridge, MA. Our team always strives to provide the most technologically advanced fiber optic solutions for our clients. Our main goal is to deliver the best quality fiber optic products to our clients. We produce a wide range of fiber optic devices, including our cutting-edge customized fiber optic Bragg grating product line and fiber Bragg grating sensor systems. Optromix, Inc. 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

Fabrication and Applications of Fiber Optic Products

Fiber optic devices have revolutionized the world of network communication ever since their inception nearly four decades ago. Nowadays these devices have almost obliterated traditional methods of networking, which use metallic wires. The evolution of optical fibers in the field of not only telecommunications but also monitoring and sensing is conducted, particularly in remote or harsh environments. In this connection, the discovery of photosensitivity in optical fibers led to the establishment of fiber Bragg gratings (FBGs), optical filters, that have been widely employed in telecom and as measurement elements.

The history of optical fiber began with the invention of the “optical telegraph” by the French Chappe brothers (1780). This “optical telegraphs” was the system comprised of a series of light mounted on towers where operations transmitted messages from one tower to another. Almost a hundred years later, in 1870, John Tyndall demonstrated that light follows the curve of a stream of water pouring from a container. It was this simple principle that led to the study and development of applications for this phenomenon. Nowadays fiber optic devices are fiber optic cable systems consisting of a multitude of glass tubes that find a host of uses in a variety of fields. Precisely speaking, fiber optic cables are cables that contain several thousands of optical fibers in a protective, insulated jacket. The optical fibers are very thin strands of pure glass, which transmit information in the form of light. Fiber optic applications have become increasingly more integrated into networks where they facilitate telecommunication applications. These fiber optic cables are often used in medicine during surgeries as light guides and imaging tools. Fiber optic products are also used in industrial settings for imaging locations that are difficult to reach through conventional means.

Fiber optic products become more and more popular in a variety of industries and applications. There are two types of optical fibers:

Single-mode fiber. The core of the glass fiber is much finer than in multi-mode fibers: light travels parallel to the axis, creating little pulse dispersion. Data transmission modes are higher, and the distances that single-mode fiber can cover can be over 50 times longer than multi-mode fibers. Telephone and cable television networks install millions of kilometers of this fiber every year.
Multi-mode fiber. Multi-mode fibers allow different data streams to be sent simultaneously over a particular fiber.

Fiber optic devices have a multitude of advantages and benefits over the more traditional methods of information systems such as copper or coaxial cables:

Speed

One of the greatest benefits of using fiber optic systems is the capacity and speed. Light travels faster than an electrical system which allows faster delivery and reception of information;

Immunity to electromagnetic interference

Fiber optics are not affected by external electrical signals because the data is transmitted with light;

Security

Optical systems are more secure than traditional mediums. These circumstances make fiber optic systems extremely attractive to governments, banks, and companies requiring increased security of data;

Fire prevention

Fiber optic systems use light instead of electricity to carry signals, the probability of an electrical fire is eliminated;

Data signaling
Less expensive

Such services as the Internet are often cheaper because fiber optic signals stay strong longer, requiring less power over time to transmit signals than copper-wire systems, which need high-voltage transmitters;

Large bandwidth, small weight, and small diameter
Easy installation and upgrades
Long-distance and transmission

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line: fiber Bragg grating sensors, FBG interrogators, and multiplexers, Distributed Temperature Sensing (DTS) systems. We create and supply a broad variety of top-notch fiber optic solutions for the monitoring of various facilities all over the world.

If you are interested in Optromix FBG sensors, please contact us at info@optromix.com

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Fiber Optic Products for Aircraft Structural Health Monitoring

FBGs for aircraft health monitoring Aircraft structures require regular, scheduled inspections and monitoring of all possible hazards due to their special conditions and the principles of their design. Therefore, structural health monitoring is conducted through fiber optic devices and has great potential to reduce the costs related to these operations. Fiber optic devices applied to the monitoring of aircraft structures provide some advantages over traditional devices. Fiber Bragg grating sensors have proved to constitute the most promising technology in this field. In order to prolong the operation period of all kinds of complex engineering systems and avoid catastrophic failures, so it is necessary to achieve the highest levels of damage detection. The automation of the inspection process is a point of major importance to reduce inspection efforts. The structural health monitoring system on the basis of fiber optic products can be defined as a set of devices that provide information that allows us to locate, evaluate, and predict the loading and damage conditions of a structure. The structural health monitoring of aircraft structures can conduct real-time checks, reducing costs, and improving the reliability and performance of the structures. A wide range of potential structural health monitoring technologies is being developed to meet these needs, and the most promising options are:

electrical strain gauges and crack wires
acoustic emissions methods
optical-based technologies
comparative vacuum monitoring
microelectromechanical systems (MEMS)

Fiber optic products and fiber optic devices, in general, are very appropriate to perform structural health monitoring due to the fact that they have their intrinsic capabilities, such as sensitivity to electromagnetic radiation, low weight, compact size, great sensitivity and resolution, and their suitability to be embedded into structures. Fiber optic devices for monitoring the strain in aircraft structures can be classified into the following categories: intensity-based, interferometric, distributed, and grating-based fiber optic devices.

Among grating-based sensors, FBGs and probably the most mature and widely employed optical sensors for structural health monitoring of engineering structures due to their fast development achieved in recent years. Fiber Bragg grating sensors have important advantages over conventional strain sensors:

high sensitivity and resolution, low weight and small size, the absence of the electromagnetic interference
suitability for being attached to a structure or embedded in composite materials
high multiplexing capability
wavelength-encoded sensing in a way that is totally independent of the optical intensity
different magnitudes can be measured using FBGs, such as strain, temperature, vibration, or humidity.

If you are interested in Optromix FBG sensors, please contact us at info@optromix.com

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Performance of fiber Bragg gratings in radiation environments

The developments in photonics led to a communication revolution over the past two decades. The technologies developed for telecommunications are now being used in the development of sensors for a wide variety of applications. The sensors based on photonic technology are especially valuable for applications where the measurements need to be taken in harsh environments like ones encountered in space exploration and nuclear power plants. Fiber Bragg grating sensors are preferred as they are compact in size, have low power consumption, and are tolerant to environmental influences.

The sensing in FBG sensors relies on using the sensitivity of the device to changes in the refractive index of the host material. In FBG sensors the resonant condition is directly proportional to the refractive index of the waveguide. A small change in the environment, for example, a temperature drop or increase, leads to a significant change in resonance wavelength which has been used for photonic thermometry. The sensitivity of FBG sensors to small changes in the refractive index raises the question of the FBG sensor performance under harsh conditions, such as high radiation environments.

The past studies have shown that FBG sensors are fully functional for several years under exposure to radiation doses ranging from a few Gy/h to a few kGy/h. Some studies have indicated a small, but significant drifts in Bragg resonances; this suggests that the resonance wavelength redshifts with increasing dose rate, however, other studies have reported a blue shift of comparable magnitude.

Overall, FBG temperature sensors show significant peak center drift due to accumulated dose, however, the temperature sensitivity shows no changes. The changes in the measurements are assumed to be due to the complex changes in the fiber. An understanding of the changes that occur in the fiber during the exposure to radiation could enable integrated dose measurements of absorbed radiation dose with the use of appropriate correction factors.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line: fiber Bragg grating sensors, FBG interrogators and multiplexers, Distributed Temperature Sensing (DTS) systems. We create and supply a broad variety of top-notch fiber optic solutions for the monitoring of various facilities all over the world.

If you are interested in Optromix FBG sensors, please contact us at info@optromix.com

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Voltage measurements with fiber Bragg gratings

Voltage measurement is essential for many fields such as power grids, telecommunications, metallurgy, railways, oil production, etc. Voltage measurements are related to fault detection and monitoring of the state of large equipment, which is essential for these fields. As the technologies used in these fields continue to develop, voltage monitoring becomes increasingly more important to the system of fault location.

Traditional voltage-sensing devices and methods are not ideal and possess multiple drawbacks, such as:

Narrow bandwidth;
Large weight;
A possibility of combustion under heavy working conditions;
Contact sensing.

Due to the multiple drawbacks of these methods, a need for a new voltage sensor has emerged. The new method of voltage measurement needs to have good amplitude-frequency characteristics and transmission characteristics in order to build smart sensing systems.

Currently, the biggest emphasis is put on fiber optic technology. Researchers attach great importance to voltage monitoring with optical elements as they offer multiple advantages that are vital for voltage monitoring in various fields:

FBG sensors are passive;
They are immune to electromagnetic interference;
FBG sensors are compact and lightweight;
FBG sensors can be mounted on any surface;
They possess a wide sensing range;
FBG sensors are stable under high temperatures.

The use of FBG sensors for voltage measurements allows us to obtain the data of switching overvoltage and lightning invasion overvoltage, analyze the overvoltage incidents, and overvoltage mechanisms.

Optromix R&D team, established in 2004, has extensive experience in the development of fiber optic products and solutions, based on the advanced research work and patents of internationally recognized scientists. Our main goal is to deliver the best quality fiber optic products to our clients. We produce a wide range of fiber optic devices, including our cutting-edge customized fiber optic Bragg grating product line and fiber Bragg grating sensor systems.

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Fiber Bragg grating for shallow landslide triggering detection

Shallow landslides pose a serious threat to structures situated in close proximity. The most dangerous are some flow-like landslides that travel at significant rates for long distances. The detaching area is the starting point for flow slides that erode and engage large amounts of soil along their path and may discharge great impact energy to engineering structures.

The detection of landslide triggers has been an important issue for many years; significant efforts have been undertaken to understand the mechanisms responsible for landslide triggering, as well as to identify the first signs of soil instability. This information will aid in the development and implementation of effective early warning systems. Among triggering, factors for a landslide are slope saturation, groundwater seepage, excavation, erosional processes, seismic action, etc. All these factors increase shear stress and pore water pressure, which in turn cause sliding surfaces due to high strain in the sliding mass. The strain increases with the approach of flow sliders; the strain increases exponentially as the landslide approaches. Soil instability follows, which causes erosion.

Therefore, the strain is the most important parameter for landslide monitoring. In recent years, fiber optic technology has attracted significant interest due to the multiple advantages that it provides. Fiber optic strain sensors are already widely used in geotechnical applications, including landslide monitoring. recently, the results of experiments involving FBG strain sensors have revealed that FBG sensors can be successfully used for measuring strain in the soil since it is possible to effectively couple the fiber cable with the soil.

One of the most attractive attributes of FBG strain sensors for landslide triggering detection is that FBG sensors do not interfere with the phenomenon that they are designated to monitor.

If you are interested in Optromix FBG strain sensors, please contact us at info@optromix.com

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Fast fiber Bragg grating sensors

Numerous advantages of fiber Bragg grating sensors, like compact size, passive nature, immunity to electromagnetic interference, the capability to directly measuring physical parameters such as temperature and strain, have inspired researchers to develop FBG sensor systems for applications outside laboratories. FBG sensors are now used in mainstream sensing technology applications. One of the recent developments in fiber Bragg grating technology is FBG sensors based on femtosecond lasers. These sensors are promising for use in extreme environments, such as high temperatures, high pressures, and ionizing radiation. Multiple industries might benefit from fast FBG sensors, like energy production applications.

Fiber Bragg grating temperature sensors that are inscribed with femtosecond lasers are stable up to the fiberglass transition temperature.

FBG sensors that are thermally stable can be used in a variety of applications. For example, stable FBG temperature sensors are optimal for sensing in extreme conditions that are often present within power plants, combustion systems, turbines, and in the aerospace sector. Regular FBG sensors do not perform optimally under extreme temperatures as they are hampered by optical losses that are a result of ingress of high-temperature hydrogen gas. However, FBG sensing arrays are difficult to produce in pure silica core fiber. The use of pure silica prevents the detrimental effects that hydrogen gas has on the fiber.

Fast FBG-based sensors have already been tested at a power generation plant. Many energy production processes require accurate temperature measurements that are difficult to realize with standard sensor technology, like electronic thermocouples. The advantages of FBG temperature sensors deployment are ease of installation, high density of sensing points, more rapid response to thermal changes, etc. Overall, fast FBG temperature sensors are an optimal solution for extreme environments, including high temperatures and high pressures. They are easy to install, maintain, are cost-effective, and accurate.

If you are interested in Optromix fiber Bragg grating temperature sensors, please contact us at info@optromix.com

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Fiber Bragg grating sensor systems in structural health monitoring

FBG sensors for structural health monitoring A traditional way of monitoring structural health is through the use of piezoelectric transducers; these devices convert pressure to an electric voltage. Transducers are reliable and accurate in most working conditions except in cases of corrosive environments or under high temperatures, above 300° Celsius. Harsh conditions influence reliability. accuracy, and usefulness of transducers in a negative way.

A new solution for structural health monitoring has been developed to accommodate the needs of the industry. Fiber-optic based technology, like fiber Bragg grating sensors, are more reliable under harsh conditions such as high temperatures and corrosive environments; they are immune to electromagnetic interference that is detrimental to piezoelectric transducers’ operation. FBG sensors are designed to operate under harsh conditions and provide reliable data. Fiber Bragg grating sensors are able to measure a variety of factors, such as temperature, strain, pressure, the appearance of cracks, etc.

The reliability of FBG sensors for structural health monitoring is ensured by the simplicity of the optical fiber material—fused silica—that forms the fiber. FBG strain sensors and FBG pressure sensors are especially useful in monitoring the condition of critical infrastructures operating under harsh environments, such as modern superheaters or nuclear power plants, thus ensuring the continuous operation of power plants, preventing catastrophic consequences of structural failures.

One of the applications of FBG sensors is the monitoring of the P91 pipes widely used in the industry. These pipes transmit high-pressure steam, which is both high-temperature and corrosive. Fiber Bragg grating temperature sensors indicate overheated pipes that may be under too much stress. FBG pressure sensors are used to detect critical increases in pressure within pipes to prevent premature breakdown of the systems.

One of the advantages of fiber Bragg grating sensing systems is its cost-effectiveness. FBG sensors’ price is low compared to other methods of temperature, strain, and pressure measurements.

If you are interested in Optromix FBG sensors, please contact us at info@optromix.com

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Fiber Bragg grating sensors for harsh environments

FBG sensors for harsh environments The demand for data is growing exponentially, piling pressure on networks to deliver more data, faster, over longer distances. Fiber optic systems have greatly improved data transfer and the gathering of information. However, complex applications require fiber optic systems to perform flawlessly, therefore, the choice of the right sensors is crucial.

The design of innovative fiber Bragg grating sensor systems has been pushed by the new societal and technological trends, such as increased mobility. Customers are looking for more data that is delivered faster both indoors and outdoors. Fiber optic sensing systems provide an easy way to install fast and reliable data links that are able to carry large amounts of data. The use of FBG sensors is expanding rapidly as they are adapted to harsh and extreme environments. It is important, however, that customers determine specific technical requirements and evaluate the possible conditions of use. FBG sensors systems provide multiple advantages that determine their wide application use. First of all, FBG sensors are able to withstand extremely high and low temperatures in a range of -40°C to +85°C. FBG sensor systems are immune to corrosion, are resistant to salt mist, vibration, and shock. The sensors are easy to handle and mount on any surface, and their coating protects them from any outside influence and significantly reduces maintenance.

One of the areas of application of FBG sensing systems is the oil and gas industry. FBG sensors are used to decrease costly downtimes and accidents during the extraction of natural resources in hazardous offshore and onshore environments. The dependable operation of FBG sensors allows for efficient extraction. Fiber Bragg grating sensors have also improved the performance of seismic evaluation devices, monitoring, and infrastructure maintenance.

We are dedicated to delivering the best products and supports to all our customers, our engineers have extensive experience and strong technical expertise in creating fiber Bragg grating products.

If you would like to purchase FBG sensors, please contact us: info@optromix.com or +1 617 558 9858

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Fiber Bragg grating sensors in for the monitoring of storage nuclear fuel pools

FBG sensors for nuclear fuel monitoring Recent events in the nuclear industry have shown the weaknesses in the control of the critical systems that ensure the safety of the nuclear plant. The extreme and accidental conditions, such as high temperatures and high levels of radiation sabotage the security of nuclear power plants, leading to major disasters. The main issue for the nuclear industry is to enhance the security of existing nuclear power plants and improve the design of the future ones. In the case of emergency or accidental conditions in nuclear reactors the following thermodynamic parameters need to be known in order to facilitate appropriate actions: temperature, pressure, water level, radiation level. The accuracy of the obtained information directly influences the decisions made by the operators. The monitoring instruments used inside the nuclear fuel pools need to better withstand severe conditions that occur during malfunctions and accidents, namely high temperatures and high levels of radiation. The strict safety regulations have pushed the fiber optic market to develop sensors based on optical fibers. Optical fiber sensors, like FBG sensors and DTS systems, have attracted interest from the nuclear plant industry for their ability to withstand harsh conditions.

Optical fiber properties depend on the temperature, strain, pressure, etc., therefore the fiber itself can be used as a sensitive element of the sensor. FBG sensors have been tested in various harsh environments and have shown consistent resistance to various harsh conditions. The immunity of FBG sensors to high temperatures, high levels of radiation, electromagnetic influence makes them an ideal monitoring solution for nuclear power plants. FBG sensors are easily mounted on any surface, are cost-effective, and require low maintenance.

There are several types of FBG sensor types that are designed to measure specific parameters. FBG temperature sensors provide long-range, long-term deployments, have a long reliability period, and have a compact size. FBG temperature sensors also provide the fastest response rate, which is especially important for emergencies and accidents.

Fiber Bragg grating (FBG) pressure sensors perform spectral analysis of the reflected wavelength to measure different parameters. Like all fiber optic sensors, FBG pressure sensors are compact and portable. FBG pressure sensors can measure high-speed events, which is essential for the localization of malfunctions inside the nuclear fuel pots.

The ability to withstand harsh conditions is the most attractive quality of FBG sensors. The use of sensors based on fiber optic technology has the potential to significantly increase the security of nuclear power plants.

Optromix is a fiber Bragg grating (FBG) sensor, vendor. We create advanced fiber optic technologies and our client’s satisfaction is our top priority. We deliver cutting-edge hi-tech products, yet we offer competitive pricing and rapid delivery time. If you want to purchase FBG temperature sensors, FBG pressure sensors, please contact us at info@optromix.com

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