about Fiber Bragg Gratings (FBG), FBG Sensors and Monitoring Systems

Quasi-distributed fiber optic sensor based on fiber Bragg gratings

on April 1, 2019

At the present time distributed optical fiber sensors based on Raman, Brillouin, and Rayleigh scattering play a crucial role in the area of monitoring due to their ability to measure strain or temperature distributions. Nevertheless, weak signals within optical fibers cause numerous challenges, such as limited spatial resolution, low measurement speed, high system complexity, or high cost of the system. That is why new technology that replaces the previous one and is called a quasi-distributed fiber optic sensing based on fiber Bragg gratings is developed now.

суперThe fact is that over the last decades, fiber optic sensors have become one of the fastest growing and promising areas of modern sensing technologies. Thus, distributed fiber optic sensing has been successfully employed in numerous strain- or temperature-sensing applications because of the multiple benefits of many sensing points and a long sensing range. Nevertheless, weak signals create new difficulties in the monitoring process.

The use of fiber Bragg grating (FBG) sensors is the only solution to the problem because FBG sensors have stronger reflection signals within an optical fiber. As a result, it is possible to use the technology for obtaining numerous physical and chemical parameters from discretized local points of a few millimeters along a single optical fiber. Moreover, these fiber optic sensors based on fiber Bragg grating can be easily multiplexed for assurance of high measurement speeds.

Unfortunately, at the moment fiber Bragg grating sensors have several drawbacks. The first is the limit of fiber optic sensors for FBG interrogation systems based on multiplexing. Thus, the maximum available number of sensors is considered to be a few tens or less. The second drawback of FBG sensors is a relatively high cost of the writing of periodic grating that is needful for the assurance of high reflectivity at different Bragg wavelengths. This is the reason why fiber optic sensors based on fiber Bragg grating are not suitable for mass production.

Herewith, a novel real-time quasi-distributed fiber optic sensor with weak fiber Bragg gratings allows increasing the number of FBG sensors up to 31 for the successful and efficient process of interrogation. Such a system does not require special maintenance, has a long lifetime because its most components are optical fibers and semiconductor tools that can be easily found in the optical industry.

Finally, this FBG system offers the following advantages that can find numerous applications in the near future:

  • high linearity;
  • high speed;
  • high stability against harsh environmental factors such as vibration, temperature, and humidity.

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

editorQuasi-distributed fiber optic sensor based on fiber Bragg gratings

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