Demodulating device of multi-channel high-precision fiber grating sensing and demodulating method thereof

Abstract

The invention discloses a demodulating device of multi-channel high-precision fiber grating sensing and a demodulating method of the demodulating device of the multi-channel high-precision fiber grating sensing. According to the demodulating device of the multi-channel high-precision fiber Bragg grating sensing, a broadband light source, a turnable FP filter and a light amplifier are connected in series and form a turnable laser, and high-stability high-power turnable laser output is obtained. Reflected signal amplitude of a fiber bragging grating serves as dynamic feedback, and an electronic control variable optical attenuator is used for dynamically adjusting the optical power decrement corresponding to each fiber grating wavelength in real time. Therefore, a sending signal optical power with the high signal to noise ratio and the stable amplitude is obtained under the condition of each fiber grating wavelength. Unevenness of the light source and array arrangement of fiber grating sensors and unpredictable dynamic changes of the fiber grating sensors in the process of utilization are compensated compressively. Therefore, long-term detection ability and the detection precision of the fiber grating sensors are effectively improved. In addition, the demodulating device of the multi-channel high-precision fiber grating sensing and the demodulating method of the demodulating device of the multi-channel high-precision fiber grating sensing have a good application prospect in the aerospace field, in the aviation field, in the petrifaction field, in the construction field and in the power field.

Description

technical field [0001] The invention belongs to the field of optical fiber grating sensing. The demodulation device and method can be used for demodulation of various strain, temperature, pressure and other sensors based on optical fiber gratings, and the application occasions include aerospace, aviation, petrochemical, civil engineering and electric power. Background technique [0002] Fiber Bragg grating sensing system uses light as the carrier and optical fiber as the medium. In addition to the advantages of small size, light weight, wide bandwidth, high sensitivity, strong anti-electromagnetic interference and strong corrosion resistance, it is also an absolute code for wavelength, not affected by optical power fluctuations, integrating sensing and transmission, and easy to use. Manufactured and embedded in the material, the measurement of stress, strain, temperature and other physical quantities has been realized. Compared with traditional electrical sensing systems, t...

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Problems solved by technology

[0004] However, in actual applications, after each fiber grating is installed and wired, the amplitude of the reflection spectrum will change, especially as the measurement environment changes, such as in an ultra-low temperature environment, when the wiring is bent too much, the fixing glue deteriorates and the fiber is coated The deformation of the layer material will lead to unpredictable dynamic changes in the fiber transmission loss and the amplitude of the reflection spectrum of the fiber Bragg grating, which will increase the difference in the reflection amplitude of multiple channels in each channel, and some reflection peaks of the fiber Bragg grating cannot be detected and fail.

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