| In the field of strain measurement, most of the reported fiber Bragg grating (FBG) sensor systems focuse on the multiplexing capability and measurement accuracy, while the strain measurement bandwidth and response rate are neglected, which has limited the application of FBG sensor system in high speed dynamic strain measurement. The purpose of this paper is to design an ultra-fast quasi-distributed strain measurement system based on FBG sensor, which can monitor high speed dynamic strain in real time.Firstly, according to the analysis on the strain measuring principle, the demodulation and multiplexing technology in the FBG sensor system, an ultra-fast quasi-distributed FBG strain sensor system demodulation and multiplexing technology is achieved by simultaneously using the time division multiplexing (TDM) technology, the wavelength division multiplexing (WDM) technology, and the combination of matched grating demodulation method. Without the scanning filters or the channel selection devices used in the traditional FBG sensor systems, an all optical multiplexing and demodulation technique is realized in the quasi-distributed strain measurement. This scheme can reduce the cost of quasi-distributed FBG sensor system and greatly improve the demodulation rate and response rate, which reveals the potential applications of quasi-distributed FBG sensor system in the field of high speed strain measurement.This paper focuses on the hardware design of the system. The design of the optical system and printed circuit are completed, and the performance of the whole system is analyzed. The strain distribution and intensity of the target object can be successfully measured in our proposed ultra-fast quasi-distributed FBG strain sensor system. The demodulation rate is10KHz for10channels after data processing. Therefore, the system could simultaneous detect the dynamic strain signal less than5-KHz with100μs response time for10channels. |
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