FBG multicore fibers are used as medical tools

FBG sensors in medicineIt is highly essential to have accurate spatial information of a medical device inside the patient for proper manipulation of the instrument. The thing is that a wide range of clinical applications requires spatial information. Nevertheless, each technique has its disadvantages, the promising solution is the application of fiber optic sensors in the catheter for its spatial information.

Fiber sensors are applied in various medical devices such as endoscopes and catheters. Such features as compact size, flexibility, lightweight, immunity to electromagnetic interference, and compatibility with medical imaging modalities make fiber optic sensors ideal for the medical environment. Therefore, FBG sensors are used in different studies to offer feedback from medical tools, they allow monitoring of muscle fatigue, cardiac activities, and body temperature.

Moreover, the application of fiber optic sensors also includes cardiovascular diagnosis, artery pressure detection, artery detection, intra-aortic balloon pumping, prostatic implants, and urology. For instance, FBG sensors are employed as force sensors to determine the interface between various tissues in order to help in precisely installing a catheter in the epidural space. 

Additionally, sensors based on FBG multicore fibers are used in numerous different shape sensing applications. “They have been used for 3D shape recognition of solid objects, shape recognition of flexible morphine wing, and curvature detection of a continuum manipulator.” Nowadays the studies describe the application of FBG sensors in single-core optical fiber but there are also FBG multicore fibers.

To be more precise, FBG multicore fibers can work as a curvature sensor and 3D shape sensors. Although their cost is higher than in single-core optical fibers, the cross-sectional area of the shape sensor with FBG multicore fibers is smaller than the shape sensor with single-core fibers. Herewith, certain devices require the use of FBG multicore fibers because of the limited space. Also, the cores of multicore optical fibers are mechanically coupled, and the relative distance between the cores remains constant, while they experience identical temperature. Such features of FBG multicore fibers make them more beneficial than single-core optical fibers.

Finally, fiber Bragg grating sensors (FBG) written on multicore optical fibers are applied as shape sensors for flexible devices. Several FBG multicore fibers have been uniquely tested as a shape sensor for a catheter. More particularly, 4 multicore optical fibers are applied despite a single multicore fiber with 3 or more cores that have FBG sensors is enough for reconstructing the shape of a flexible device. Several multicore optical fibers expand the reliability of the sensing system against individual FBG sensor failure.

Optromix is a manufacturer of innovative fiber optic products for the global market. The company provides the most technologically advanced fiber optic solutions for the clients. Optromix produces a wide range of fiber optic devices, including cutting-edge customized fiber optic Bragg grating product line and fiber Bragg grating sensor systems. Moreover, Optromix 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

DTS performs dam monitoring

DTS for dam monitoringDams applied for hydropower, irrigation or mining play a crucial role in human life, herewith, they evoke significant human, economic, and environmental consequences when they fail. Nevertheless, distributed fiber optic sensing increases dam safety by offering early alerts of potential problems.

To be more precise, modern distributed sensing systems are considered to have high accuracy for monitoring promoting a continuous understanding of dam conditions, taking dam safety to a higher level. For instance,  distributed temperature sensing (DTS technology) uses high spatial resolution temperature data from distributed temperature sensors to record tiny seepage flow changes and to estimate seepage rates in a dam structure. 

It should be noted that seepage happens in most embankment and earth dams as the impounded water looks for the path of least resistance through the dam and its foundations. Therefore, excessive seepage presents a threat while high-tech sensing systems enable to detect and analyze subsurface processes and prevent erosion. Distributed fiber optic sensing is a promising technology that can be employed to control critical geophysical parameters, for instance, temperature and strain with a sub-meter resolution over several km. 

Additionally, distributed sensing systems provide the benefits of cost-effective high spatial monitoring coverage. The thing is that optical fiber acts as the sensing system along the full length of the fiber optic cable allowing operators to obtain detailed data information along the entire dam. Distributed temperature sensors can catch tiny, localized changes in the seepage flow rates that would otherwise remain unnoticed. “They deliver temperature readings with the accuracy of point sensors with the indisputable benefit of fiber optics: the highest possible spatial coverage. ”

Moreover, the distributed temperature sensing does not need specialized optical fibers resulting in relatively low-cost installation. The thing is that measurements based on DTS systems provide data along the entire dam with high spatial resolution and high-temperature precision. Herewith, distributed temperature sensors have already been used in tailings dams. One of the main elements of the increasing number of permanent tools is the ever-increasing performance of the DTS systems. Modern fiber optic sensing systems achieve the world’s most accurate measurements, with sampling resolutions of 12cm (over 5km) and with temperature resolution as low as 0.01 C.  

Finally, seepage detection used distributed temperature sensing is regarded as a crucial technology and has prominently improved the monitoring capabilities of dam operators. The application of optical fiber networks provides additional benefits like the ability of distributed sensing systems develops further.

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

Fiber Bragg gratings in bogie frame

FBGs for bogie frameThe application of fiber optic technology as temperature and strain gauges is quite surprising in bogie frames. To be more precise, these fiber optic sensors are applied for examining the carbon fiber bogie, in addition to standard surface-mounted electrical-resistance fiber optic strain gauges.

Optical fibers of 125 micrometers in diameter or 250 micrometers with a coating layer are perfect for this aim. The thing is that the optical fiber is improved to produce fiber Bragg gratings (FBG) in the fiber, efficiently producing a number of semi-reflective mirrors over short but equal intervals.

The operating principle of the FBG system is based on the reflection of the signal (a small amount of the signal at each semi-reflective mirror) when the light is transmitted through a fiber Bragg grating. Herewith, “the originally reflected wavelengths (without the influence of strain) from each Bragg grating are compared to the reflected wavelengths when the structure is loaded.”

It should be noted that in the case of FBG deformation by strain, the spacing between the semi-reflective mirrors is either enlarged (tension) or decreased (compression). Therefore, the change combined with the efficient refractive index and the period of the fiber Bragg gratings leads to a shift in the reflected central Bragg wavelength.

The thing is that the wavelength size demonstrates the strain magnitude. Nevertheless, there is the same effect that happened with temperature change, while the temperature effect is over 10 times the strain effect that is why the fiber optic technology needs to correct for temperature.

The researchers present the techniques applied to compensate for temperature where the fiber Bragg grating is placed close to the end-face of a cleaved optical fiber. The fact is the optical fiber with FBG is put in a capillary tube where one end is fused to the fiber, well away from the grating, and the opposite end is sealed. Finally, the FBG system responds only to temperature.

Nonetheless, it is not enough only to install several strain gauges into the bogie and link them to the instrumentation either. Ir is required to choose the proper fiber, for instance, bend-insensitive optical fibers are suitable. These are optical fibers where the diameter of the core includes 9.5-micrometer fibers with 4.5 mm long fiber Bragg gratings.

Additionally, it is necessary to properly install FBG systems to the bogie so as to act as a homogeneous part of the structure. Fiber Bragg gratings provide such benefits as efficient strain gauge transfer, capable to accommodate localized variations in the surface topology of the composite.

Optromix is a manufacturer of innovative fiber optic products for the global market. The company provides the most technologically advanced fiber optic solutions for the clients. Optromix produces a wide range of fiber optic devices, including cutting-edge customized fiber optic Bragg grating product line and fiber Bragg grating sensor systems. Moreover, Optromix 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