While electrical sensors are widely used, they have limitations due to their sensitivity to EMF (electromagnetic interference) and electrical signal loss. For this reason, there is a growing need to replace electrical sensors with optical sensors that monitor temperature, stress, displacement and acceleration on machinery, equipment, planes, buildings, bridges and other devices and structures. Structures containing these new sensor types are often referred to as “Smart Structures.” Fiberguide Industries, a leader in fiber optic assemblies, has partnered with Micron Optics, a leader in fiber optic sensing, to develop innovative products that allow for monitoring strain, temperature, displacement and acceleration.
For decades, electrical sensors have been the standard for measuring physical and mechanical changes. But electrical sensors fall short in regard to transmission loss and susceptibility to noise—electromagnetic interference. The need for long distances, or compatibility with various environments alongside the potential electromagnetic interference, often render electrical sensors impractical. However, because fiber-optic sensing utilizes light rather than electricity, it is a great solution in many situations.
Optical fibers can be constructed such that the cores have short segments of Fiber Bragg Gratings that
reflect back particular wavelengths of light while transmitting all others. Fiber Bragg Gratings are made by laterally exposing the core of a single-mode fiber to a periodic pattern of intense ultraviolet light, producing a permanent increase in the refractive index of the fiber’s core, whose pattern creates a fixed index modulation. This grating reflects back particular wavelengths of light while being transparent to all the other wavelengths.
When fiber optics monitor and collect data, users do not have to worry about EMPs because EMPs do not affect light transmission. Also, remote monitoring is possible because light signals in optical fibers do not degrade over long distances, as electricity through copper wires does. Fiber optics are also very small and can fit in compact locations. Fiber optic sensors can also be multiplexed, allowing many sensors in a single fiber.
Each of these features benefit civil engineers needing to monitor buildings, bridges, and other structures, aerospace engineers monitoring aircraft and space crafts, and mechanical engineers needing to monitor mechanical assemblies, windmills, cars, trains, oil wells, and many other devices. Sensors can monitor strain, temperature, displacement and acceleration.
Fiber Bragg Gratings in optical fibers avoid the pitfalls of electric sensors and allow, through serial multiplexing capacity, the monitoring of multiple signals and locations via one fiber. These features, combined with their ability to provide absolute measurements without any need for referencing, makes them a natural alternative to electrical sensors.
For over thirty years, OEM manufacturers looking for a reliable, long-term, strategic partner in providing efficient, cost-effective, practical fiber optic solutions engineered to meet their specific needs have turned to Fiberguide Industries. Our focus is manufacturing large-core specialty optical fiber, high-temperature metalized optical fibers, and packaging these fibers in a variety of assemblies/bundles for optical power delivery—and now, optical sensing applications. Fiber Bragg Gratings allow us to increase optical sensor capability for improved sensor performance.
To learn more about Fiberguide’s product innovations, visit Fiberguide.com today!
Author: Kevin Rauscher