Russian Scientists Create 'Emergency-Alerting' Fiber

“The international research team under Alexander Kiryanov, NUST MISIS Professor of the Semiconducting Electronics and Physics of Semiconductors Department, together with the Optical Research Center (Leon, Mexico) and Central Glass and Ceramic Research Institute (Kolkata, India) has developed fiber-based high-precision sensor technology,” Alevtina Chernikova, NUST MISIS Rector, announced.

This fiber is doped with rare-earth and transition metals: erbium, holmium, bismuth, as well as nanoparticles of silver and silicon. The composition of ligands (chemical additives) and their relationship in the fiber silica are unique and account for the unique features of the fiber. The research results have been published in Laser Physics Letters magazine.

The fiber is highly sensitive to changes in temperature, pressure, chemical composition and background radiation, as well as highly resistant to aggressive environments and electromagnetic disturbances. Those features are useful in high-precision monitoring of large-scale objects such as pipelines, boreholes, nuclear power plants and bridges. A defined fiber length helps with the measuring of large objects (up to 100 meters). In low Earth orbit, fiber-based sensors can measure background radiation in space equipment and flaws on its surface.

With high efficiency and precision, such fiber-based sensors can detect various radiation types in a wide range of doses, ultra-high (up to 1700°С) temperatures, chemical composition and electromagnetic fields. The fiber length provides for remote measuring, for example, full-scale monitoring of a deep oil well, mine, pipeline, or nuclear power plant systems. Due to its unique features, the fiber-based devices will be in high demand in the construction, geotechnology, aerospace and oil-and-gas industries, as well as heavy-current (including nuclear) power generation.

A fiber sensor is either a small “pinpoint” sensor (which in turn can be a part of multicomponent detection networks, or interrogators), or a “spatially-distributed circuit” that can collect information on detectable parameters at large distances (“distributed sensor”).

In the first case, Bragg gratings (spectral-selective filters) can be the sensor’s sensing elements. Their parameters, i.e. reflection-absorption and transmission spectra, depend heavily on the environment – pressure, temperatures and deformations – and thus become the detection basis.

In the distributed sensor the sensing element is the whole length of the fiber: it is either used in passive mode (and then the detectable parameters are, for example, changes in the absorption and transmission spectra of the doped fiber), or in active mode when it becomes a laser component (and then the detectable parameters are, for example, relaxation frequency, optical spectrum or laser oscillation regime).

According to head of the project Alexander Kiryanov: “This research’s aim is to create, thoroughly study and use fiber sensors of the second type with specially-designed doped fiber, including the ones we obtained through nano-engineering. This fiber can be a reliable solution while working in aggressive environments, when the fiber-based device is put in extreme conditions: for example, in thermo-monitoring of oil wells or nuclear power plant dosimetry.”