The fiber optic sensors also called as optical fiber sensors use optical fiber or sensing element. These Sensors can measure a large variety of parameters, such as temperature, pressure, strain, refractive index, vibrations, displacements, bending, loading, and liquid level or concentration of chemical species. Fiber optic sensors have become a focus in the field of sensing technologies by right of their many advantages such as compact, light-weighted, high sensitivity, high multiplexing, anti-electromagnetic interference and easy to be embedded into material. Following the development of optical fiber communication industry, the optical fiber sensing technologies become another major industry of optoelectronic technologies
Fiber-optic sensor consists of optical source (Light Emitting Diode, LASER, and Laser diode), optical fiber, sensing element, optical detector and end-processing devices (optical-spectrum analyzer, oscilloscope). The optical fiber consists of the core and the cladding, which have different refractive indexes. The light beam travels through the core by repeatedly bouncing off the wall of the cladding. The light beam, having passed through the fiber without any loss in light quantity, is dispersed at an angle of approximately 60° and emitted to the target.
Fundamentally, fibre-optic sensors make use of optical fibre as an essential element to transfer and amplify the quantity to be measured. An optical-fibre cable receives light beam as input, which is nothing but the quantity to be measured, as sensed by input of the sensor. Input for the cable is provided by a broadband light source such as LED, or narrow-band light source such as laser diode.
The fiber laser acts as the optical light source within a sensing element, and can achieve high signal-to-noise ratio, high sensitivity, long distance sensing, and multi-parameter sensing. The wavelength shift can be calculated using a device, optical frequency-domain reflectrometry. The time-delay of the fiber optic sensors can be decided using a device such as an optical time-domain Reflectometer.
Fiber optic sensors are supreme for insensitive conditions, including noise, high vibration, extreme heat, wet and unstable environments. The optical fiber sensors have advantages like immunity to electromagnetic interference, lightweight, small size, high sensitivity, large bandwidth, and ease in implementing multiplexed or distributed sensors. The fiber optic sensor allow for detection in tight spaces or where a small profile is beneficial. They are resistant to high temperature and explosive environment. No possibility of spark, so are safe to be used in hazardous sensing environments, such as oil refineries, grain bins, mining operations, pharmaceutical manufacturing and chemical processing
Over the past decade, optical fiber sensors have gained widespread acceptance within the oil and gas industry due to their reliability, flexibility and low operating costs, as well as the benefits brought by their multipoint and distributed sensing capabilities. More recently, extensive interest has been shown in the development and commercialization of fiber optic seismic and acoustic sensing arrays – land and underwater – for oil and gas exploration, pipeline surveillance, geophysical monitoring, reservoir monitoring and management, geothermal monitoring, and structural monitoring of offshore platforms and oil tankers. Distributed acoustic sensing (DAS) enables detection, discrimination and location of acoustic events on an optical fiber over tens of kilometers.
Hydrophones are used for seismic and sonar applications. Hydrophones with more than 100 sensors per fibre cable have been developed. Hydrophone sensor systems are used by oil industries and in the navies of some countries.
Fiber-optic gyroscopes and fiber-optic current sensors are good examples of rather mature and commercialized optical fiber sensor technologies. Fiber optic gyroscopes (FOGs) are critical tools in many different platforms; aircrafts, missiles, unmanned aerial vehicles (UAVs), and ground vehicles all require advanced optical fiber navigation technology to ensure reliability and safety.
Fiber Optic Sensors
These sensors are classified into three categories based on the operating principles, sensor location and application.
Optical-fibre sensors can be classified as follows:
According to location of sensor: intrinsic fibre-optical and extrinsic fibre-optical. In intrinsic type of sensor sensing takes place within the fibre. This means that the fibre is directly affected by the measured quantity. Here, one of the physical properties of light signal may be in the form of frequency, phase, polarization; intensity. The most useful feature of the intrinsic fiber optic sensor is, it provides distributed sensing over long range distances.
In extrinsic type, the optical fibre is used as the information carrier. These sensors are used to measure rotation, vibration, velocity, displacement, twisting, torque and acceleration. The best example of this type of sensor is the temperature sensor inside an aircraft jet engine. It uses optical fibre to transmit radiation into a radiation pyrometer, which is located outside the engine. In the same way, these sensors are used to measure internal temperature of transformers.
Based on operating principles: intensity, phase and polarisation
Intensity based fiber optic sensors require more light and these sensors use a multi-mode-large core fibers. In a phase based sensor, a light beam is passed through the interferometer, then the light separates into two beams. Wherein one beam is exposed to the sensing environment and the other beam is isolated from the sensing environment, which is used as a reference. In polarization based sensor, the phase difference between the two polarization states is changed under any external disturbances such as stress or strain.
Based on application: chemical, physical and bio-medical:
A chemical sensor is a device which is used to transform chemical information in the form of a measurable physical signal that is associated with the concentration of a certain chemical species.
A physical sensor is a device that is made according to the physical effect and nature. These sensors are used to provide the information about a physical property of the system. This type of sensors are mostly signified by sensors such as photoelectric sensors, piezoelectric sensors, metal resistance strain sensors and semiconductor piezo-resistive sensors.
Biomedical sensor is an electronic device that is used to transfer various non- electrical quantities in biomedical fields into easily detectable electrical quantities. Due to this reason, these sensors are included in health care analysis. This sensing technology is the key to collecting human pathological and physiological information.
Some of the major disadvantages that need solutions are complex detection system, Expensive, non-familiarity to end user, requirement of precise installation procedures and usable measuring system’s development is complex
Advantages of fiber optic sensors
Compact, light weighted and low power consumption.
In general, the fiber optic sensors have complicated process technologies involving the semiconductor process, laser processing, precision machining and forming technologies, so as to make sensors smaller or more miniature. Thus, traditional bulk optic components such as beam splitters, combiners, and objective lenses have been rapidly replaced by small-sized fiber devices that enable the sensors to operate on fiber scales, typically 125 μm in diameter. Besides, the data carrying bandwidth of fiber optics is so high that hundreds and potentially thousands of sensors can be supported by a single fiber. Fiber optic sensing system could reduce their power consumption to several Watt level, by adopting the power supply with high electro-optical conversion efficiency, refrigerating efficiency and the modulator with low driven voltage.
Adaptation to application requirements in harsh environments.
In general, the environment where the fiber optic sensors are used is relatively severe. For example, to name a few, in space launch applications, the fiber optic sensors are required to survive under high impact force (peak acceleration up to 1000 g) and/or high frequency vibration (1000~5000 Hz) ; Electricity industry requires that the fiber optic sensors have high insulativity; Oil drilling and geological exploration industries require that the sensors are resistant to high temperature (up to 350 °C) and pressure (up to 60 MPa) ; Nuclear power stations require that the sensors are highly resistant to radiation.
Reliability and long life span.
For example, in some military fields, the sensors have to be very reliable to work and store for a long time, normally more than 10 years or even 20 years. In some fields (such as satellite and electricity plant), optoelectronic elements are required to work continuously for an even longer time.
New air sensor to make chemical plants safer
The number of worldwide deaths from chemical-related incidents is surprisingly common, with 681 fatalities reported in global media in 2017 alone. High profile chemical plant explosions in the past year include the Port Neches Chemical Plant explosion, Texas (November 2019), the La Canonja explosion in Spain (January 2020), and the surfactant unit explosion in Tarapur, India (April 2020), to name a few.
No technology currently exists to perform a real-time, automatic check in fuel tanks for Volatile Organic Compounds (VOCs) – chemicals that evaporate quickly at room temperature. Technologies that are generally used to monitor these chemicals currently use electronic sensors that need to be heated past 150 degrees. Emptying giant tanks filled with alcohols, ketones, aldehydes, chloroform, and dichloromethane, chemical plant staff have to ensure no traces of vapour or liquid remain. Having to climb inside these giant tanks, workers are under constant threat of causing an explosion from friction or static electricity.
Chemical plants will become safer places to work with a reduced risk of injury, chronic respiratory ailments or even death, thanks to a new air sensor being developed to detect toxic and explosive solvents using photonics. Scientists from the University of Navarra in Pamplona, Spain have teamed up with the EU photonics innovation hub ACTPHAST 4R to develop a demonstrator for their breakthrough optical sensing technology that detects lethal chemicals that are both dangerous to inhale and highly explosive.
This new detector uses optical fibres – the cables that carry vast amounts of data via the Internet – to monitor air quality, with no electrical or flammable components as part of the device. The optical fibre sensing solution is designed to be ideal for dangerous places where electricity is forbidden and could soon create safer working conditions for chemical plant staff who handle highly toxic and explosive chemicals. With a demonstrator ready, the researchers say it will require further testing before being commercially available.
The lead researcher on the project, Dr César Elosúa Aguado from the Electrical, Electronic Engineering and Communications Department Public at the University of Navarra, said: “An air sensor using optical fibres for the purpose of VOC detection is a major scientific breakthrough concept. It is currently in its pre-prototype, ‘demonstrator’ phase but has the potential to be further developed for industrial application. “The innovation support we have received from ACTPHAST 4R has been crucial to bridging the gap between the ‘valley of death’ in innovation and accelerated TRL advancement.
Combining several different platforms never previously considered for automated gas detection, the new sensor looks at the interaction between the cladding modes and the sensitive coating – producing a new signal when the toxic substance is present. “We still use metallic oxides but our system looks at the refractive index of the sensing material, rather than changes in electrical conductivity. “The sensor surface is coated with zinc oxide oxides as a sensing material that reacts when the harmful material is present.” “Cladding modes are a part of the optical signal that is “forced” to travel by a Bragg reflector, not through the core but around the cladding, enabling an interaction with the surrounding media,” Dr Elosúa Aguado said. The sensor is therefore specifically ‘tuned’ to a toxic substance, meaning the only molecules that are captured along the sensor are those dangerous gasses. The reactivity to the gas (known as ‘selectivity’) will depend on VOC molecular properties, such as polarity.
Today’s electronic sensors use metallic oxides that are capable of sensing toxic chemicals but are not safe in the shipping of chemical solvents. When exposed to VOCs, semiconductor metallic oxides show a change in electric resistivity and have been used to develop electronic sensors for many years but can be unsafe and slow to use in dangerous environments. Dr Elosúa Aguado said: “We want to create the safest chemical plants ever made, putting workers lives and well-being first. This technology allows instantaneous, real-time monitoring and not having to wait days for samples to come back from a laboratory”.
“The reaction mechanism between the metallic oxide and the VOC is a reversible redox chemical reaction. The selectivity of these materials is low, so they react to a wide range of solvents with different sensitivities. Therefore, sensors with different responses combine to form a specific pattern for each VOC.” “The sensor response will be used to train an artificial intelligence system capable of identifying the different VOC samples,” said Dr Elosúa Aguado.
If the demonstrator is successful, the researchers will look at commercialisation options such as licensing or a spin-out company from the university, to take it to the next stage of a working prototype and eventually a full commercial product.
Chinese researchers develop Optical Strain Sensor for Wearable Tech
A team of researchers at Tsinghua University, China, led by OSA member Changxi Yang, have developed fiber optic sensor made of a silicone polymer that can stand up to, and detect, elongations as great as 100 percent—and effortlessly snap back to an unstrained state for repeated use (Optica, doi: 10.1364/OPTICA.4.001285).
“For human-motion detection, strain sensors with high flexibility and stretchability are demanded,” he explained to Design News. “For such applications, fiber-optic strain sensors offer attractive advantages such as inherent electrical safety, immunity to electromagnetic interferences, and small size. However, the low stretchability and stiffness of the conventional optical fibers, typically made of glass or plastics, are fundamental limits for measurements of large deformations.”
Tsinghua researchers used fibers made of polydimethylsiloxane (PDMS), a soft, stretchable silicone elastomer that’s become a common substrate in stretchable electronics. The team developed the fiber by cooking up a liquid silicone solution in tube-shaped molds at 80 °C, and doping the fiber mix with Rhodamine B dye molecules, whose light absorption is wavelength dependent. Because stretching of the fiber will shrink its diameter, leaving the total volume invariant, a fiber extension has the effect of increasing the optical length for light passing through the dye-doped fiber. That increase, in turn, can be read in the attenuation of the fiber’s transmission spectra, and tied to the amount of strain in the fiber.
In tests Yang’s team found that a 4-cm length of the fiber, with a diameter of 0.5 mm, repeatedly held up to strains on the order of 100 percent, snapping back to its original length with no change even after 500 cycles. The team found that the sensor measured strains with an error of less than 0.6 percent over repeated measurements, and that bending of the fiber didn’t materially reduce its effectiveness as a strain sensor.
The technology has the potential to be used in a wide array of applications, including wearable smart devices for medical, entertainment, or sporting and fitness uses, Yang said. “For example, the flexible and stretchable strain sensors can be mounted in different parts of the body and function for the sport-performance monitoring,” he said. “The data can be used for the body-movement analysis during sport activities, which are beneficial for the continuous health and wellness monitoring, and evaluation of athletes’ sport performances.”
Robotics is another area of potential use, with the strain sensors being used to actuate smart robots to remotely control a gripper robot by measurements of the finger-joint motion, Yang added. “Flexion or extension of fingers can be used to control the robot to perform surgical procedures or delicate and dangerous tasks that are out of reach for the human body,” he said.
Distributed optical fiber sensors (DOFS)
Distributed optical fiber sensors (DOFS) offer unprecedented features, the most unique one of which is the ability of monitoring variations of the physical and chemical parameters with spatial continuity along the fiber. Distributed optical fiber sensors (DOFS) can measure lots of sensing parameters distributedly along the fiber under test (FUT) such as strain, stress, vibration, temperature, 3D shape, flow rate, refractive index, magnetic field, radiation, gas, etc, which are very useful for many sensing applications. Presently, most of the research groups have moved their focus towards distributed sensors, capable of detecting various dynamic parameters including dynamic strains, electromagnetic fields and sound waves
Several DOFS technologies have been developed based on the measurement of intrinsic backscattering, including Raman, Brillouin and Rayleigh scattering, which are based on optical time domain reflectometry (OTDR) and optical frequency domain reflectometry (OFDR). In OTDR, the input pulse generated is launched into the fiber under test (FUT). As the input pulse propagates along the FUT, the light from the pulse that gets back-reflected light either via Rayleigh backscattering or Fresnel reflection is then measured by using a photo-detector. The sensing range to the point of reflection is dependent on the time delay between the input light pulse and the corresponding back-reflected light.
Among all the distributed sensing techniques, OFDR has been given tremendous attention because of its high spatial resolution and large dynamic range. A basic OFDR configuration consists of a tunable laser source (TLS) which optical frequencies can be tuned linearly in time without any mode hops and an interferometer that comprises a test path and a reference path. The reference path is considered as a local (LO) oscillator whereas the FUT is connected to the test path.
Interferences are generated between the LO signals and back-reflected light in FUT coming from the test path that contains Rayleigh backscattering and Fresnel reflection. The beat frequencies are obtained by a Fourier transform applying to the interferences signals. If the tuning rate of the TLS is a constant, the beat frequencies are proportional to the length of FUT
One extremely beneficial use for fiber laser sensors is in the development of seismic sensor arrays that can operate in underwater conditions, making it useful in earthquake detection, borehole monitoring, and ocean bottom cabling systems. Acting like a hydrophone, it can detect seismic signals reliably and therefore is also useful in towed array sonar systems, which can typically be found towed behind submarines or surface ships. This is useful for many industries, especially security, military, and oilfield-exploration.
Fiber optic seismic sensors have been increasingly recognized as promising technologies for many applications, such as intruder detection and perimeter defense systems. Among these, a military seismic sensor is especially challenging because it requires a robust, compact, reliable, easily installable and operated product
Fiber sensors can also be used in the medical field to deliver a more efficient patient diagnosis, monitoring and treatment with handy devices such as handheld scanners, which for instance can be used to quickly and reliably detect brain injuries. This can be useful in a variety of different areas, such as up ski slopes or on a battlefield, where quick detection could be vital, and yet sometimes not easily attainable without a device such as the one mentioned above.
Some newer types of fiber laser are able to have a much larger level of wavelength tuning, reaching further into the mid-infrared spectrum than has previously been achieved. This means that it can operate within the same wavelength where many gases, including greenhouse gases, absorb light. Therefore, some fiber laser sensors will be able to detect levels of greenhouse gases from a great distance.
All-optical magnetic field sensors promise MRI system alternative
Researchers at the University of Arizona, Tucson, have developed a light-based technique for measuring very weak magnetic fields, such as those produced from neurons firing in the brain and heart.
Fabricated using optical fibers and a newly developed polymer-nanoparticle composite that is sensitive to magnetic fields, the sensors can detect the brain’s magnetic field, which is 100 million times weaker than the magnetic field of earth. The inexpensive and compact magnetic sensors, say the researchers, could offer an alternative to the large and costly magnetic resonance imaging (MRI) systems currently used to map brain activity by avoiding the expensive cooling or electromagnetic shielding required by MRI machines.
“A portable, low-cost brain imaging system that can operate at room temperature in unshielded environments,” says researcher member Babak Amirsolaimani, “would allow real-time brain activity mapping after potential concussions on the sports field and in conflict zones where the effect of explosives on the brain can be catastrophic.”
In addition to brain activity, the researchers showed that the new sensor can detect the weak magnetic pattern of a human heartbeat – demonstrating the technology’s potential as a simple replacement for electrocardiography, or ECG, tests commonly performed to detect heart problems – and has the capability to detect magnetic fluctuations that change every microsecond from an area as small as 100 square microns.
“The all-optical design of the sensor means it could be fabricated inexpensively on a silicon photonics chip,” says Amirsolaimani, “making it possible to produce a system that is almost as small as the sensor’s 10-micron-diameter optical fiber. Multiple sensors could then be used together to provide high spatial resolution brain mapping.”
The new sensors, say the researchers, could help scientists better understand the activity of the brain and diseases of the brain such as dementia and Alzheimer’s. In addition, they may also be useful for measuring the magnetic fields used to predict volcanic eruptions and earthquakes, identify oil and minerals for excavation, and detect military submarines.
The sensors work by taking advantage of the fact that a magnetic field causes the polarization of light to rotate, with the degree of rotation dependent on the material through which the light passes. The researchers developed a new composite material made of magnetite and cobalt nanoparticles – materials with very high magnetic sensitivity – dispersed in a polymer that imparts a detectible polarization rotation in light when very weak magnetic fields are present.
The researchers detected the polarization rotation using an optical interferometer , which works by splitting laser light into two paths – one of which passes through the highly-sensitive material while the other does not. The polarization of each light path is detected and compared to measure fluctuations in very small magnetic fields.
As noise can easily cover up the desired signal being detected, the researchers used an interferometer setup that eliminated ambient environmental effects such as vibration and temperature fluctuations. The setup kept noise levels very close to the theoretical limit of the optical design, which was key for detecting very weak magnetic fields.
Looking ahead, the researchers next plan to study the long-term stability of the sensors and how well they withstand environmental changes. They also want to fabricate several hundred sensors to make a system for evaluating and imaging the entire magnetic field of a human brain.
As well as being able to act as seismic sensors at the bottom of the ocean, fiber laser sensors are also able to withstand incredibly high levels of heat, meaning they can be found in technology such as microwave ovens. They can also handle other harsh environments such as high-voltage, high-power machinery, and so have become useful and necessary sensors for heavy electrical equipment such as generators or motors. They are also much less likely to get damaged if lightning strikes nearby.
Industrial elements—such as furnaces of all kinds, sintering operations, ovens and kilns, automated welding and more—often generate large electrical fields where conventional sensors cannot be used. High temperature processing operations, as in refractories and chemical industries, often use optical-fibre sensors. These are also used in fusion, sputtering and crystal growth processes in semiconductor industries.
In comparison with traditional electromechanical or electronic sensors, the fiber optic sensors have relatively high potential to work in hypersonic wind tunnel. Hypersonic wind tunnel experiment technologies are involved to many subjects such as aerodynamic forces, aerothermodynamics, thermal protection of aircraft structures, heat-fluid-solid coupling, hypersonic boundary layer, air-breathing propulsion system and light-weighted and high-strength material, and so on.
Saab and Rolls-Royce are undertaking a joint research programme into fibre-optic sensing technologies for aerospace propulsion systems.
Fibre-optic sensing technologies have the potential to provide a novel solution that acquires multiple measurements such as strain, pressure and temperature along a single wire. Compared to existing technologies, this low-weight integrated solution could offer higher temperature and accuracy within the harsh operating environment of an engine. Such advanced measurement systems compliment the journey to the Intelligent Engine and enhanced data driven engine services.
Known as Project FibreSense, this collaborative research programme between Rolls-Royce and Saab will develop and demonstrate fibre-optic sensing technology for aerospace propulsion systems. The research will take place within the Eureka Network projects programme as a joint initiative between the Swedish Innovair and the British Aerospace Technology Institute (ATI). Eureka is an international co-operation programme supporting collaborative market-oriented research and development projects for innovative products, processes and services. This joint initiative between the UK and Sweden aims to develop project proposals which have strong market potential in these countries and globally.
Laser Sensor Can Detect Damage to Military Assets
A distributed feedback fiber laser sensor has detected acoustic emission signatures associated with cracks in riveted lap joints, demonstrating that it has the potential to uncover structural damage in U.S. Navy assets before the damage reaches critical levels.
Developed by researchers at the U.S. Naval Research Laboratory (NRL), the laser sensor consists of a single fiber, similar in width to a human hair, which is integrated into a shallow groove formed in the lap joint. The sensor has a small system footprint and can be multiplexed.
To test the technology, researchers installed the laser sensors into a series of riveted aluminum lap joints and measured acoustic emission over a bandwidth of 0.5 megahertz (MHz) generated during a two-hour accelerated fatigue test. They took equivalent measurements with an electrical sensor.
The embedded laser sensors demonstrated acoustic sensitivity comparable to or greater than that achieved by existing electrical sensors. The laser sensors were able to detect low-level acoustic events generated by periodic fretting from the riveted joint, in addition to acoustic emissions from crack formation. Time-lapse imagery of the lap joint revealed that the observed fracture correlated with the signals measured. In addition to crack detection, the fiber laser sensor also showed the ability to measure compromising impacts.
“Our research team has demonstrated the ability of this fiber laser technology to detect acoustic emission at ultrasonic frequencies from cracks generated in a simulated fatigue environment,” said Dr. Geoffrey Cranch, research physicist. “The novel part of this work is the fiber laser technology and how it is being applied.
The fiber laser sensor system has now been expanded to multiplex many sensors onto a single fiber. Efforts are underway to interpret the acoustic emission data to calculate metrics such as probability of failure. Future enhancements may include implementing phased array beam forming techniques to facilitate crack location.
The fiber laser sensor also has the potential to integrate with existing fiber optic strain and temperature sensing systems. Integrating the sensor with these systems would provide a multiparameter sensing capability that could meet the operational safety requirements for an SHM system at significantly lower cost.
“An automated, in-situ structural health monitoring (SHM) system, capable of monitoring key structural parameters such as temperature, strain, impacts and cracks, and capable of reliably detecting damage well before reaching a critical level is needed to increase safety and readiness while lowering operational cost of Navy platforms” said Cranch. “At present, none of the services are using in-situ technologies to manage the structural health of their assets.”
“Our focus is on Navy platforms, such as aircraft, ships and submarines, but the technology could also be used on civilian aircraft,” he said. “Applications to bridges and buildings are also possible if there are critical parts prone to fatigue and failure that would benefit from continuous monitoring.”
Future trends in the fiber-optic sensors field can be briefly summarised as follows:
Special wave guides, such as photonic crystal fibres, will enable many new sensing mechanisms and sensor configurations. Improved micro-fabrication technologies will continue to improve sensor performance, functionality and reliability.
Advanced signal processing and networking technologies will enable high-density fibre-optic sensor networks.
Plasmotronics is yet another promising new trend in electronics. Researchers have found that plasmons can be effectively used in optical-fibre cables to enhance their capabilities. Here, plasmons are used instead of photons (light particles). Thus, fibre-optic plasmonic sensors utilise both propagation and localised surface plasmon resonance techniques.
Recent research has presented a cost-effective and rugged approach to apply nanoparticles to optical-fibre cables. Use of nanoparticles on coatings of fibre-optic cables leads to enhanced sensor response. These particles provide several advanced abilities to sensors, such as real-time monitoring, multiplexing capabilities, remote sensing, small dimensions, bio-compatibility and much more.
Progress in photonic sensor designs and applications continues at a fast pace with new types of optical fibers – photonic band gap fibers (PBG), microstructure optical fibers (MOF), random hole optical fibers (RHOF); and hybrid ordered random hole optical fibers (HORHOF); higher resolution, lower cost, and or expanded detection range capability for sources and detection schemes; and new signal demodulation algorithm designs.
The global distributed fiber optic sensor market is expected to witness a CAGR of 15.0% during the forecast period, to reach $1,970.1 million by 2023. Distributed fiber optic sensors are widely being adopted in oil and gas vertical. In oil and gas applications, these sensors are being used for specific monitoring of well-temperature and for obtaining an authentic picture of physical parameters of wellbore.
However, the market is expected to register fastest growth in civil engineering vertical, during the forecast period. Distributed fiber optic sensors are widely being adopted in civil engineering to enhance the inspection accuracy and efficiency.The application of structured health monitoring (SHM) systems to civil engineering is the major factor escalating the adoption of distributed optic fiber sensors in this vertical. Engineers trained in visual inspection used to execute several civil engineering infrastructures including assessment of buildings, bridges, dams and tunnels, which includes the probability to be inaccurate because of the deviations in their background for safety condition assessments. These sensors help civil engineering vertical with their features of durability, small size, security and insensitivity to external electromagnetic perturbations.
Some of the major players in Global Fiber Optic Sensor Market includes ABB Ltd. (Switzerland), Yokogawa Electric Corporation (Japan), OmniSens S.A. (Switzerland), Deltex Medical Group PLC (UK), Finisar Corporation (U.S.), AP Sensing GmbH (Germany), Sumitomo Electric Industries Ltd. (Japan), AFL Group (U.S.), Luna Innovations Incorporated (U.S.), and, others.