Distributed Acoustic Sensing (DAS) in exploring the ocean

DAS in exploring the oceanExploring the underwater environment that covers most of the Earth’s surface is one of the most difficult tasks. The easiest way is the usage of distributed acoustic sensing (DAS) technology. However, the fbgs sensors’ setting is also not so easy because of the environmental conditions. Despite this fact, distributed acoustic sensing has a huge potential for observing processes in the future.

Fiber optic solutions are the new methods of geophysical information registration that can be applied both onshore and offshore. The scientists used transmission time-of-flight of laser pulses inside transoceanic subsea fibers to note seafloor strain. To explore seafloor strain with higher spatial resolution, they utilized a distributed acoustic sensing (DAS) system.

Distributed acoustic sensing technology helps to observe the ocean and solid earth phenomena. The scientists applied a fiber optic cable and a distributed acoustic sensing (DAS) unit operating onshore. DAS technology uses a photonic device that sends short pulses of laser light through fiber optics. DAS detects the backscattering set by strain in the cable caused by stretching.

The researchers could get even more data than expected. They could record underwater earthquakes, volcanic activity, and a range of micro hydrodynamic signals. The scientists monitored the acoustic waves by alterations in laser light along the fiber optic cable. Recordings of a small earthquake wavefield demonstrated several fault zones underwater. Distributed acoustic sensing could picture earthquake hazards in the coastal oceans and give new data about fault orientations and seafloor structures. The DAS system displayed the state of the sea and its changes during a storm cycle. These observations proved the necessity and potential of this method for marine geophysics.

There are still aspects of this distributed acoustic sensing research that should be improved. One of them is the fact that current DAS instruments can only see lower frequencies. However, such frequencies are considered to be low for acoustics, but it is high for seismologists and enough to locate boat signals. The research team also explores the possibilities of tracking mammals, for example, whales with the help of distributed acoustic sensing technology. The second challenge is the fact that the scientists don’t know where exactly the fiber optic cable is. Because seabed bathymetry can affect the signals and influence DAS senses. Nowadays, it is possible to use only the initial part of the fiber optic cable, up to 200 km. But it already allows capturing a number of spheres of science.

As a result of the research, the observations with the DAS system during just a few days helped to create a map of an unknown fault system and detect several dynamic processes in the water. The distributed acoustic sensing technology could help to get rid of a huge gap in ocean sensing.

According to the researchers, the production of fiber optic systems based on the DAS technology can be easily automated. However, there is still a space for developing and finding new ways of optimization.

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

Fiber Bragg Gratings (FBG) sensors’ applications

FBG sensors' applicationsThe sensing technology market has a rapid growth in the last few decades. Most of all, this is explained by the main advantages like small size, environmental and electrical immunity, and distribution capabilities. The new units of FBG sensors and fiber optic cables are valuable instruments for monitoring industrial processes and infrastructure. That’s why fiber Bragg grating (FBG) sensors are applied in many different spheres.

Fiber Bragg grating (FBG) sensors are becoming more popular each year because fiber optic applications are spreading in different aspects of life and science. Some of them are security, transportation, civil engineering, medical, and etc.

Despite the diverse application space, the market driver for fiber Bragg grating sensors has been monitoring smart structures like bridges, dams, and pipelines. FBG sensors also have had an impact on the aerospace industry by controlling the temperature, vibration, strain, and other data in real-time.

There are a lot of fiber optic applications in the oil and gas industry. Fiber Bragg grating technology, fiber optic monitoring systems, and distributed temperature sensing are commonly applied for in-well temperature monitoring and exploration activities. Distributed fiber optic sensors are also widespread in the wind power industry. They are used for the measurement of stress and strain in turbine blades.

In medicine, the ability to perform all the fiber optic solutions’ benefits is very useful for operations and certain medical procedures. Fibers can be inserted in hypodermic needles or catheters. That allows for more precise positioning of the fiber optic sensors. Moreover, fiber Bragg grating sensors are applied for temperature profiling near patients’ internal organs. And finally, FBG sensors are produced for endoscopic/colonoscopic pressure profiling.

Fiber optic technology has an impact on chemical and biochemical sensing. There are bioassays based on fiber Bragg gratings as the sensing element for protein or DNA interactions.

Nowadays, because of the development of fiber optic solutions, new fiber Bragg gratings were created. They are able to cope with high temperatures and harsh environments. It is highly useful and even crucial in power plants and for combustion and jet engines.

Today FBG sensors are becoming irreplaceable tools in different fields because of their simplicity in comparison with other technologies and advantages that they provide. And according to the tendency, fiber Bragg grating sensors will continue to apply in many existing and emerging applications.

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

Distributed Acoustic Sensing (DAS) system for Arctic tests

DAS system for Arctic tests The USA researchers started a number of experiments that aim to analyze the first data about seafloor under Arctic sea ice with the usage of a new method. The research team was able to connect a distributed acoustic sensing (DAS) system with a fiber optic cable. The cable vibrations can record the data 24/7. That helped the scientists to get all the activities and changes within the ocean all day long. This was the first time in history when a DAS system was used on the seafloor of the Arctic or Antarctic oceans.

The appliance looks like an electronic box that is attached to the fiber optic cable on land. It uses a laser to send thousands of short pulses of light. The small amount of the light is reflected back. And the reflected light helps the appliance to monitor events along with the fiber and store the data on hard drives.

According to the research, the DAS technology showed the icequakes, different climate signals, and marine life. The researchers are expecting to note other climate signals like ocean wave height, timing, and distribution of sea ice breakup, and ice thickness, etc. The usage of the distributed acoustic sensing system has the potential to record a variety of Arctic phenomena so the scientists can better see the climate change effects and sea life. Moreover, the DAS system makes it cost-effective and safe in comparison with the other methods. The scientists have already recorded a number of events that the traditional hydrophone or ocean bottom seismometers couldn’t even detect. With the help of the DAS system, the scientists hope to also record whale songs.

However, the research team has to face challenges during the first week of the tests. And the most difficult one was the harsh climate. It was really cold, most of the territory is tundra. It’s snowing most of the time and it’s getting dark really early. No wonder, that the team should find new creative ways of data fixing like DAS technology to get everything working.

That’s why the researchers chose a distributed acoustic sensing system to cope with the weather conditions. Fiber optic cable is double-armored with copper and steel. All the network components are created to hold the extreme Arctic environment. They have no need in sending a boat to plant monitors, moving over the sea ice to install the sensors. This fiber optic cable can exist for years or decades without replacing it.

This project of watching the Arctic ocean with the usage of the distributed acoustic sensing system is going to last over the next two years. The research team will collect the data. And the next third year will be spent on its analysis.

According to the researchers, the production of fiber optic systems based on the DAS technology can be easily automated. However, there is still a space for developing and finding new ways of optimization.
Optromix is a DAS system manufacturer that provides top of the line distributed acoustic sensing systems suitable for monitoring commerce networks. If you have any questions or would like to buy a DAS system, please contact us at info@optromix.com

FBG sensors as a part of a mercury detection system

Fiber Bragg Grating sensors as a part of the mercury detection systemResearchers from India have presented a new development. Thanks to it the scientists can find toxic mercury in drinking water. The whole system is based on FBG sensors.

Fiber Bragg grating (FBG) sensors are utilized widely in industrial and commercial applications with the addition of fiber optic solutions. FBGS sensors are especially effective in stabilizing the wavelength of semiconductor lasers and are useful in extracting a single wavelength from the fiber. Fiber Bragg grating sensors are popular in different spheres, including aerospace, robotics, the oil and gas industry, etc. Achievements in creating fiber optic sensors and their applications make the Fiber Bragg grating sensors appropriate for other spheres and developments.

That’s why scientists from India decided to apply Fiber Bragg grating sensors to the mercury detecting system. We can find mercury particles everywhere in the environment. They can be produced not only by human-made causes, like industrial wastes but also by natural ones, for example, combustion of fossil fuels and volcanic eruptions. That’s why the creation of the mercury detection system with the help of FBG sensors was a very important step.

According to medical studies, mercury particles can easily enter the human body. The most common ways are water bodies and marine life. In the human gut, some microorganisms can turn mercury into organic and alkyl forms. These forms of mercury in the human blood-vascular system can lead to diseases of kidneys, nerves, endocrine, and other systems. So the mercury detection system based on fiber Bragg grating sensors plays a crucial role in health care activities.

The developed by the research team FBG sensors are portable in comparison with other traditional techniques. These techniques are gas chromatography and liquid chromatography methods were tested by time. They are considered to be precise and complicated. And they are not portable like fiber Bragg grating sensors. Moreover, they need much time and get more expenses because are made in special laboratories by professionals.

Scientists think that fiber Bragg grating sensors are an ideal decision for the developing mercury detection system. Fiber Bragg grating principles help to make this system cost-expensive and highly effective in comparison with the others. However, they agree that there is still a lot of work to do and Fiber Bragg grating sensors can be updated in the future.

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