Fiber optic sensing technology for electrical safety monitoring is a cutting-edge application discipline emerged in this century. Using both fiber optic sensing signals and fiber optic transmission signals, it is currently the most outstanding representative of sensing technology. It is a revolutionary technology for automatic detection. Fiber optic grating sensing is a new type of all-fiber passive device, which has incomparable advantages and characteristics compared to ordinary sensors. It is intrinsically explosion-proof, electrically safe, chemically stable, transmits over long distances, and can be used for absolute measurement of external parameters, which has caused a revolution in the sensor field. Its industry has been recognized both domestically and internationally as one of the most promising high-tech industries, being highly regarded for its high technical content, good economic benefits, strong penetration capabilities, and broad market prospects. Due to its inherent advantages, fiber optic sensing technology will inevitably replace traditional sensing technology in the near future. The fiber optic grating sensing system is mainly composed of a broadband light source, fiber optic grating sensor, and signal demodulation.
The performance of the light source directly determines the performance of the entire system. In fiber optic grating sensing, the light source must have a wide bandwidth and strong output power and stability to meet the needs of multi-point and multi-parameter measurement in sensing systems. Currently, commonly used light sources in fiber optic grating sensing systems include SLED and ASE light sources.
The fiber optic grating sensor can directly measure physical quantities such as temperature and strain. Since the fiber optic grating wavelength is sensitive to both temperature and strain at the same time, i.e., temperature and strain simultaneously cause fiber optic grating wavelength shift, there is no way to distinguish between temperature and strain by measuring fiber optic grating wavelength shift alone. Therefore, solving the cross-sensitivity problem and realizing the distinction between temperature and stress measurement is a prerequisite for the practical application of the sensor. Currently, commonly used technologies for fiber optic grating sensing in the sensing system all utilize two or two segments of fiber optic grating with different temperature and strain response sensitivities to form a dual-grating temperature and strain sensor, and to determine the responsiveness coefficients of different fiber optic gratings to temperature and strain.
In the fiber optic grating sensing system, signal demodulation is the key, which mainly includes two parts: one part is optical signal processing, which completes the conversion of optical signal wavelength information to electrical signal, and the analysis of the center reflection wavelength of the sensor is critical for demodulation; the other part is electrical signal processing, which completes the operation and processing of the electrical signal, extracts external information, and displays it in a way that people are familiar with.
Therefore, the fiber optic grating safety monitoring system adopts digital measurement technology, which has higher stability and safety compared to traditional measurement technology.