Fiber Bragg raster sensing device based on high-speed pulse laser

Abstract

The invention relates to a fiber Bragg raster sensing device based on a high-speed pulse laser. The fiber Bragg raster sensing device includes the high-speed pulse laser, a dispersion module, a fiber Bragg raster array, a data acquisition module, and a data processing module. Based on the high-speed pulse laser, the narrow pulse being broad in band and high in repetition rate is provided, and the demodulation rate and the dynamic range of a fiber Bragg raster sensing demodulation system is greatly improved. Through the adoption of a photon time stretching method, the measurement of the wavelength shift of the optical fiber Bragg raster in the frequency domain is converted to the measurement of the time shift in the time domain, and the signal processing precision of the time domain is higher. Therefore, the demodulation precision of fiber Bragg sensing system can be significantly improved, and the requirement on the sampling rate of the data acquisition and processing modules is also reduced.

Description

technical field [0001] The invention relates to a method and a device in the field of optical fiber sensing, in particular to a fiber Bragg grating sensing device based on a high-speed pulse laser. Background technique [0002] Optical fiber has dual functions of sensing and transmission, and has the advantages of light weight, anti-electromagnetic interference, high temperature resistance, and corrosion resistance. In addition to the advantages of general optical fiber sensors, fiber Bragg grating sensors also have strong multiplexing capabilities and distributed sensing. Advantage. In recent years, fiber Bragg grating sensors have received great attention and developed rapidly, and have been widely used in the monitoring fields of strain and temperature in intelligent buildings, civil engineering, medical engineering or other extreme environments. Fiber Bragg grating sensing is mostly wavelength modulation. The traditional demodulation method can be roughly divided into t...

AI Technical Summary

Problems solved by technology

Fiber Bragg grating sensing is mostly wavelength modulation. The traditional demodulation method can be roughly divided into two types due to different detection methods. The first one is based on passive detection, that is, using a frequency discriminator to convert the Bragg wavelength shift into optical Intensity change or spatial displacement of light intensity, this method can be realized by edge filter, arrayed waveguide grating, wavelength division multiplexer or spectral charge coupled device based on holographic grating, its advantage is that the system is simple and economical, but the light source The jitter or environmental interference may be reflected back as the signal of the sensor, resulting in low demodulation accuracy. In addition, passive detection is also difficult to achieve high-speed dynamic sensing [A.Fender, E.J.Rigg, R.R.J.Maier, W.N. MacPherson, J.S.Barton, A.J.Moore, J.D.C.Jones, D.Zhao, L.Zhang, I.Bennion, S.McCulloch, and B.J.S.Jones, “Dynamic two axis curvature measurement using multicore fiber Bragggratings interrogated by arrayed waveguidegrating,” Appl. Opt., vol. 36 pp.9041-9048, Dec.2006]

The second is active detection, which converts the displacement of the Bragg wavelength into the phase change of the received signal based on optical interferometry. For interferometers or long-period fiber gratings, the measurement accuracy of active detection is much higher than that of passive detection because it eliminates the jitter of the light source. The vibration is very sensitive, so it will affect the stability of the system. In addition, the demodulation speed based on the active detection method is limited to several thousand Hz, and the dynamic range is also small [H.Xia, C.Zhang, H. Mu, and D. Sun, "Edge technique for direct detection of strain and temperature based on optical time domain reflectometry," Appl. Opt., vol.48, no.2, pp.189-197, Jan.2009]

Images